As filed with the Securities and Exchange Commission on February 14, 2003

                                                    Registration No. ___________

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                ----------------

                                    FORM S-3
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                                ----------------

                             SIGA Technologies, Inc.
             (Exact name of registrant as specified in its charter)

              Delaware                                13-3864870
   (State or Other Jurisdiction of        (I.R.S. Employer Identification No.)
    Incorporation or Organization)

                              420 Lexington Avenue
                                    Suite 601
                            New York, New York 10170
                                 (212) 672-9100
              (Address, including zip code, and telephone number,
        including area code, of Registrant's principal executive office)

                                ----------------

                               Thomas N. Konatich
                         Acting Chief Executive Officer
                             SIGA Technologies, Inc.
                              420 Lexington Avenue
                                    Suite 601
                            New York, New York 10170
                                 (212) 672-9100
            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                                -----------------

                                    COPY TO:

                            Thomas E. Constance, Esq.
                       Kramer Levin Naftalis & Frankel LLP
                                919 Third Avenue
                            New York, New York 10022
                                 (212) 715-9100



      Approximate date of commencement of proposed sale to the public: From time
to time as determined by the Selling Stockholders.

      If the only securities being registered on this Form are being offered
pursuant to dividend or interest reinvestment plans, please check the following
box. |_|

      If any of the securities being registered on this Form are to be offered
on a delayed or continuous basis pursuant to Rule 415 under the Securities Act
of 1933, other than securities offered only in connection with dividend or
interest reinvestment plans, check the following box. |X|

      If this Form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list the Securities Act registration statement number of the earlier
effective registration statement for the same offering. |_|

      If this Form is a post-effective amendment filed pursuant to Rule 462(c)
under the Securities Act, check the following box and list the Securities Act
registration statement number of the earlier effective registration statement
for the same offering. |_|

      If delivery of the prospectus is expected to be made pursuant to Rule 434,
please check the following box. |_|

                         CALCULATION OF REGISTRATION FEE



-------------------------------------------------------------------------------------------------------------------------------
                                                                    Proposed                Proposed
      Title of Shares               Number of Shares to be      Maximum Offering       Maximum Aggregate        Amount of
      to be Registered                  Registered(1)          Price Per Share(2)      Offering Price(2)    Registration Fee
-------------------------------------------------------------------------------------------------------------------------------
                                                                                                      
Common Stock, par value
$.0001 per share                          3,913,966                  $1.285              $5,029,446.31            $462.71
-------------------------------------------------------------------------------------------------------------------------------


(1)   Pursuant to Rule 416 under the Securities Act of 1933, as amended, this
      registration statement also covers such indeterminate number of shares of
      common stock as may be required to prevent dilution resulting from stock
      splits, stock dividends or similar events.

(2)   Estimated solely for the purpose of computing the amount of the
      registration fee, based on the average of the high and low prices for SIGA
      Technologies, Inc.'s common stock as reported on the Nasdaq SmallCap
      Market on February 7, 2003 in accordance with Rule 457(c) under the
      Securities Act of 1933, as amended.

      The Registrant hereby amends this registration statement on such date or
dates as may be necessary to delay its effective date until the Registrant shall
file a further amendment which specifically states that this registration
statement shall thereafter become effective in accordance with Section 8(a) of
the Securities Act of 1933 or until this registration statement shall become
effective on such date as the Commission, acting pursuant to Section 8(a), may
determine.



                                3,913,966 SHARES

                             SIGA TECHNOLOGIES, INC.

                                  COMMON STOCK

                                ----------------

      Shares of common stock of SIGA Technologies, Inc. are being offered by
this prospectus. The shares will be sold from time to time by the selling
stockholders named in this prospectus. The prices at which such selling
stockholders may sell the shares will be determined by the prevailing market
price for the shares or in negotiated transactions. We will not receive any
proceeds from the sale of shares of common stock by the selling stockholders but
we will receive proceeds from the exercise of warrants held by the selling
stockholders. Our shares are traded on the Nasdaq SmallCap Market under the
symbol "SIGA." Our principal executive offices are located at 420 Lexington
Avenue, Suite 601, New York, New York 10170. Our telephone number is (212)
672-9100.

                                ----------------

      Investing in the shares involves a high degree of risk. For more
information, please see "Risk Factors" beginning on page 3.

                                ----------------

      Neither the Securities and Exchange Commission nor any state securities
commission has approved or disapproved of these securities or determined whether
this prospectus is truthful or complete. Any representation to the contrary is a
criminal offense.

      The information in this preliminary prospectus is not complete and may be
changed. These securities may not be sold until the registration statement filed
with the SEC is effective. This preliminary prospectus is not an offer to sell
not does it seek an offer to buy these securities in any jurisdiction where the
offer or sale is not permitted.

                                ----------------

                The date of this prospectus is February 14, 2003



                                TABLE OF CONTENTS

                                                                            Page
                                                                            ----

ABOUT THIS PROSPECTUS.........................................................1

FORWARD-LOOKING STATEMENTS....................................................1

ABOUT SIGA TECHNOLOGIES, INC..................................................1

RISK FACTORS..................................................................3

USE OF PROCEEDS...............................................................9

SELLING STOCKHOLDERS..........................................................9

PLAN OF DISTRIBUTION.........................................................11

LEGAL MATTERS................................................................13

EXPERTS......................................................................13

PART II--INFORMATION NOT REQUIRED IN PROSPECTUS.............................II-1

SIGNATURES..................................................................II-4



                              ABOUT THIS PROSPECTUS

      This prospectus is part of a registration statement that we filed with the
Securities and Exchange Commission (the "SEC"). The prospectus relates to
3,863,966 shares of our common stock which the selling stockholders named in
this prospectus may sell from time to time. We will not receive any of the
proceeds from these sales but we will receive proceeds from the exercise of
warrants held by the selling stockholders. We have agreed to pay the expenses
incurred in registering the shares, including legal and accounting fees.

      The shares have not been registered under the securities laws of any state
or other jurisdiction as of the date of this prospectus. Brokers or dealers
should confirm the existence of an exemption from registration or effectuate
such registration in connection with any offer and sale of the shares.

      This prospectus describes certain risk factors that you should consider
before purchasing the shares. See "Risk Factors" beginning on page 3. You should
read this prospectus together with the additional information described under
the heading "Where You Can Find More Information."

                           FORWARD-LOOKING STATEMENTS

      This prospectus and the other reports we have filed with the SEC, contain
"forward-looking statements" within the meaning of Section 27A of the Securities
Act of 1933, as amended, or the "Securities Act," and Section 21E of the
Securities Exchange Act of 1934, as amended, or the "Exchange Act." The words or
phrases "can be", "expects", "may affect", "may depend", "believes", "estimate",
"project", and similar words and phrases are intended to identify such
forward-looking statements. Such forward-looking statements are subject to
various known and unknown risks and uncertainties and we caution you that any
forward-looking information provided by or on behalf of SIGA is not a guarantee
of future performance. Our actual results could differ materially from those
anticipated by such forward-looking statements due to a number of factors, some
of which are beyond our control, in addition to those risks discussed in "Risk
Factors" in this prospectus and in our other public filings, press releases and
statements by our management, including (i) the volatile and competitive nature
of the biotechnology industry, (ii) changes in domestic and foreign economic and
market conditions, and (iii) the effect of federal, state and foreign regulation
on our businesses. All forward-looking statements are current only as of the
date on which such statements were made. We do not undertake any obligation to
publicly update any forward-looking statement to reflect events or circumstances
after the date on which any such statement is made or to reflect the occurrence
of unanticipated events.

                          ABOUT SIGA TECHNOLOGIES, INC.

      We are a development stage technology company, whose primary focus is on
biopharmaceutical product development. Our focus is on mucosal vaccines for
strep throat and sexually transmitted diseases, commensal bacteria for the
delivery of vaccines, novel antibiotics for gram positive and gram negative
bacteria and biological warfare defense.

                                Mucosal Vaccines

      We are developing vaccines and a delivery system for these vaccines. We
are currently developing mucosal vaccines for strep throat and for sexually
transmitted diseases, or "STDs." A mucosal vaccine is a vaccine that activates
the immune system at the mucus-lined surfaces of the body--the mouth, the nose,
the lungs and the gastrointestinal and urogenital tracts--the sites of entry for
most infectious agents. The system we are developing to deliver these mucosal
vaccines uses genetically engineered commensal bacteria. Commensal bacteria are
harmless bacteria that naturally inhabit the body's surfaces, particularly the
mucus-lined areas.

Strep Throat Vaccine Candidate

      We are developing with technology we licensed from The Rockefeller
University, or "Rockefeller," a mucosal vaccine for strep throat. This vaccine
has demonstrated an ability to colonize and induce both a local and systemic
immune response in mice and rabbits. We are collaborating with the National
Institute of Health, or


                                        1


"NIH," and the University of Maryland Center for Vaccine Development on the
clinical development of this vaccine candidate. In December 1997, we, in
cooperation with the NIH, filed an Investigational New Drug Application with the
United States Food and Drug Administration, or "FDA." In September 1999, the NIH
awarded us a research grant to help support the research cost of our strep
program.

      The first stage of clinical trials was completed at the University of
Maryland in 2000. The study showed the delivery system to be well-tolerated and
that the commensal bacteria was spontaneously or easily eradicated. A second
clinical trial of the commensal delivery system without the strep throat vaccine
technology was initiated in 2000 at the University of Maryland. This trial was
completed in January 2002 and the results corroborated the conclusions of the
earlier study regarding tolerance and eradication.

Sexually Transmitted Disease Vaccine Candidates

      We are developing a mucosal vaccine for STDs utilizing technology we
licensed from Oregon State University and Washington University. We are
primarily focused on developing a vaccine for chlamydia, the most common form of
STD, and Neisseria, the agent which causes gonorrhea. As both of these STDs
enter people via mucus-lined surfaces of the body, we believe that a mucosal
vaccine will be a more effective delivery method than a traditional vaccine. In
February 2000, we entered into an agreement with the Ross Products Division of
Abbott Laboratories under which Ross provided us with funding for development of
an STD vaccine. The research program was completed in late 2001. The agreement
was extended through the first quarter of 2003 to permit an additional set of
experiments to be conducted.

                                 Anti-Infectives

      Our anti-infectives research targets infections that are acquired in
hospitals and drug-resistant bacteria. Our aim is to block the ability of
bacteria to attach and colonize human tissue and to cut off infection at the
first stage in the process. We are developing technologies to treat both major
classes of bacteria--gram-positive and gram-negative.

Gram-Positive Antibiotic Technology

      We are developing an antibiotic technology based on the research of our
founding scientists which makes it more difficult for gram-positive bacteria to
attach to human tissue. Our scientists found that most gram-positive bacteria
utilize a particular enzyme, a protease, to attach to and colonize human tissue.
Our strategy is to develop antibiotics that inhibit the generation of protease.
In 1997, we entered into a collaborative research and license agreement with the
Wyeth-Ayerst Laboratories Division of American Home Products Corporation to
identify and develop protease inhibitors. In the first quarter of 2001, we
received a milestone payment from Wyeth at the beginning of screening for
protease inhibitors. We also licensed technology from the University of
California at Los Angeles which may be incorporated into our development of
products for Wyeth.

Gram-Negative Antibiotic Technology

      We are developing a technology to inhibit the ability of gram-negative
bacteria to attach to human tissue. Gram-negative bacteria utilize structures
called pili to adhere to human tissue. We believe that inhibiting the assembly
of pili should effectively inhibit diseases caused by these structures. In July
1999 and August 2000 we were awarded research grants from the NIH to support our
development efforts in this area. We entered into agreements with Med Immune
Inc., Astra AB and Washington University, pursuant to which we acquired rights
to certain gram-negative antibiotic targets, products, screens and services
developed at Washington University. In February 2000, we ended our collaborative
relationship with Washington University on this technology, but we are still
developing the technology which we acquired in the initial agreements.

                           Biological Warfare Defense

      We are developing a host of technologies to aid in biological warfare
defense. These technologies include anti-smallpox drugs, and treatments for
toxins and infections that may be used in an act of terrorism.


                                       2


      The FDA has amended its regulations to make it easier to approve
biological warfare defense products. In addition, the U.S. federal government
increased the amount of money committed to support research in this area.

      We believe that we are particularly well-suited to contribute to this area
as our Chief Scientific Officer, Dr. Dennis Hruby, has over 20 years experience
working on smallpox-related research and has been leading a SIGA/Oregon State
University consortium working on an anti-viral drug development program since
September 2000.

                                  RISK FACTORS

      Investing in our common stock involves a high degree of risk, and you
should be able to bear losing your entire investment. You should carefully
consider the risks presented by the following factors.

We have incurred operating losses since our inception and expect to incur net
losses and negative cash flow for the foreseeable future.

      We incurred a net loss of $7.8 million for the year ended December 31,
2000, $3.7 million for the year ended December 31, 2001 and $2.3 million for the
nine months ended September 31, 2002. As of September 30, 2002 and September 30,
2001, our accumulated deficit was $28.5 million and $24.9 million, respectively.
We expect to continue to incur significant operating and capital expenditures
and, as a result, we will need to generate significant revenues to achieve and
maintain profitability.

      We cannot guarantee that we will achieve sufficient revenues for
profitability. Even if we do achieve profitability, we cannot guarantee that we
can sustain or increase profitability on a quarterly or annual basis in the
future. If revenues grow slower than we anticipate, or if operating expenses
exceed our expectations or cannot be adjusted accordingly, our business, results
of operations and financial condition will be materially and adversely affected.
Because our strategy includes acquisitions of other businesses, acquisition
expenses and any cash used to make these acquisitions will reduce our available
cash.

Our business will suffer if we fail to obtain timely funding.

      In order to commercialize our products, we will need and we intend to
obtain additional financing. Our operations to date have required significant
cash expenditures. Our future capital requirements will depend on the results of
our research and development activities, pre-clinical studies and clinical
trials, competitive and technological advances, and regulatory activities of the
FDA and other regulatory authorities. We may obtain that financing through
public and private offerings of our securities, including debt or equity
financing, or through collaborative or other arrangements with research
institutions and other third parties. If we raise additional capital by issuing
equity, or securities convertible into equity, our stockholders may experience
dilution and share prices may decline. Additionally, any financing (particularly
a debt financing) may result in contractual restrictions on our ability to spend
money, to pay dividends or to take certain other actions.

      If we are unable to obtain sufficient financing, we may need to do one or
more of the following:

      o     delay, scale back or eliminate some or all of our research and
            product development programs;

      o     license third parties to develop and commercialize products or
            technologies that we would otherwise seek to develop ourselves;

      o     attempt to sell our company;

      o     cease operations; or

      o     declare bankruptcy.


                                       3


We are in various stages of product development and there can be no assurance of
successful commercialization.

      Our research and development programs are at an early stage of
development. The FDA has not approved any of our biopharmaceutical product
candidates. Any drug candidates developed by us will require significant
additional research and development efforts, including extensive pre-clinical
and clinical testing and regulatory approval, prior to commercial sale. We
cannot be sure our approach to drug discovery will be effective or will result
in the development of any drug. We cannot expect that any drugs that do result
from our research and development efforts will be commercially available for
many years.

      We have limited experience in conducting pre-clinical testing and clinical
trials. Even if we receive initially positive pre-clinical or clinical results,
such results do not mean that similar results will be obtained in the later
stages of drug development, such as additional pre-clinical testing or human
clinical trials. All of our potential drug candidates are prone to the risks of
failure inherent in pharmaceutical product development, including the
possibility that none of our drug candidates will or can:

      o     be safe, non-toxic and effective;

      o     otherwise meet applicable regulatory standards;

      o     receive the necessary regulatory approvals;

      o     develop into commercially viable drugs;

      o     be manufactured or produced economically and on a large scale;

      o     be successfully marketed;

      o     be reimbursed by government and private consumers; and

      o     achieve customer acceptance.

      In addition, third parties may preclude us from marketing our drugs
through enforcement of their proprietary rights, or third parties may succeed in
marketing equivalent or superior drug products. Our failure to develop safe,
commercially viable drugs would have a material adverse effect on our business,
financial condition and results of operations.

Most of our immediately foreseeable future revenues are contingent upon
collaborative and license agreements and we may not achieve sufficient revenues
from these agreements to attain profitability.

      Until and unless we successfully make a product, our ability to generate
revenues will largely depend on our ability to enter into additional
collaborative and license agreements with third parties and maintain the
agreements we currently have in place. We will receive little or no revenues
under our collaborative agreements if our collaborators' research, development
or marketing efforts are unsuccessful, or if our agreements are terminated
early. Additionally, if we do not enter into new collaborative agreements, we
will not receive future revenues from new sources.

      Our future receipt of revenues from collaborative arrangements will be
significantly affected by the amount of time and effort expended by our
collaborators, the timing of the identification of useful drug targets and the
timing of the discovery and development of drug candidates. Under our existing
agreements, we may not earn significant milestone payments until our
collaborators have advanced products into clinical testing, which may not occur
for many years, if at all.


                                       4


We may face limitations on our ability to attract suitable acquisition
opportunities or to integrate additional acquired businesses.

      As part of our business strategy we expect to enter into business
combinations and acquisitions. Some of these transactions could be material in
size and scope. While we will continually be searching for additional
acquisition opportunities, we may not be successful in identifying suitable
acquisitions. We compete for acquisition candidates with other entities, some of
which have greater financial and other resources than we have. Increased
competition for acquisition candidates may make fewer acquisition candidates
available to us and may cause acquisitions to be made on less attractive terms,
such as higher purchase prices. Acquisition costs may increase to levels that
are beyond our financial capability or that would adversely affect our results
of operations and financial condition. Our ability to make acquisitions will
depend in part on the relative attractiveness of shares of our common stock as
consideration for potential acquisition candidates. This attractiveness may
depend largely on the relative market price, our ability to register common
stock and capital appreciation prospects of our common stock. If the market
price of our common stock were to decline materially over a prolonged period of
time, our acquisition program could be materially adversely affected.

      We may not be able to consummate potential acquisitions or an acquisition
may not enhance our business or may decrease rather than increase our earnings.
In the future, we may issue additional securities in connection with one or more
acquisitions, which may dilute our existing shareholders. Future acquisitions
could also divert substantial management time and result in short term
reductions in earnings or special transaction or other charges. In addition, we
cannot guarantee that we will be able to successfully integrate the businesses
that we may acquire into our existing business. Our shareholders may not have
the opportunity to review, vote on or evaluate future acquisitions.

The biopharmaceutical market in which we compete and will compete is highly
competitive.

      The biopharmaceutical industry is characterized by rapid and significant
technological change. Our success will depend on our ability to develop and
apply our technologies in the design and development of our product candidates
and to establish and maintain a market for our product candidates. There also
are many companies, both public and private, including major pharmaceutical and
chemical companies, specialized biotechnology firms, universities and other
research institutions engaged in developing pharmaceutical and biotechnology
products. Many of these companies have substantially greater financial,
technical, research and development, and human resources than us. Competitors
may develop products or other technologies that are more effective than any that
are being developed by us or may obtain FDA approval for products more rapidly
than us. If we commence commercial sales of products, we still must compete in
the manufacturing and marketing of such products, areas in which we have no
experience. Many of these companies also have manufacturing facilities and
established marketing capabilities that would enable such companies to market
competing products through existing channels of distribution.

Because we must obtain regulatory clearance to test and market our products in
the United States and foreign jurisdictions, we cannot predict whether or when
we will be permitted to commercialize our products.

      The pharmaceutical industry is subject to stringent regulation by a wide
range of authorities in the geographic areas where we intend to develop and
commercialize products. A pharmaceutical product cannot be marketed in the
United States until it has completed rigorous pre-clinical testing and clinical
trials and an extensive regulatory clearance process implemented by the relevant
regulatory authorities. Satisfaction of regulatory requirements typically takes
many years, is dependent upon the type, complexity and novelty of the product
and requires the expenditure of substantial resources.

      Before commencing U.S. clinical trials in humans, we must submit and
receive clearance from the FDA by means of an Investigational New Drug
application, or "IND." Similar regulatory requirements exist in other countries.
Clinical trials are subject to oversight by institutional review boards and the
regulatory authorities and:

      o     must be conducted in conformance with the FDA's and/or any other
            relevant regulatory authorities' good laboratory practice
            regulations;


                                       5


      o     must meet requirements for institutional review board oversight;

      o     must meet requirements for informed consent;

      o     must meet requirements for good clinical and manufacturing
            practices;

      o     are subject to continuing FDA and/or other regulatory oversight;

      o     may require large numbers of test subjects; and

      o     may be suspended by us or the applicable regulatory authorities at
            any time if it is believed that the subjects participating in these
            trials are being exposed to unacceptable health risks or if the
            applicable regulatory authorities find deficiencies in the IND
            application or the conduct of these trials.

      Before receiving regulatory clearance to market a product, we must
demonstrate that the product is safe and effective on the patient population
that will be treated. Data obtained from pre-clinical and clinical activities
are susceptible to varying interpretations that could delay, limit or prevent
regulatory clearances. Additionally, we have limited experience in conducting
and managing the clinical trials and manufacturing processes necessary to obtain
regulatory clearance.

      If regulatory clearance of a product is granted, this clearance will be
limited to those disease states and conditions for which the product is
demonstrated through clinical trials to be safe and efficacious. We cannot
ensure that any compound developed by us, alone or with others, will prove to be
safe and efficacious in clinical trials and will meet all of the applicable
regulatory requirements needed to receive marketing clearance.

If our technologies or those of our collaborators are alleged or found to
infringe the patents or proprietary rights of others, we may be sued or have to
license those rights from others on unfavorable terms.

      Our commercial success will depend significantly on our ability to operate
without infringing the patents and proprietary rights of third parties. Our
technologies along with our licensors' and our collaborators' technologies may
infringe the patents or proprietary rights of others. An adverse outcome in
litigation or an interference to determine priority or other proceeding in a
court or patent office could subject us to significant liabilities, require
disputed rights to be licensed from or to other parties and/or require us, our
licensors or our collaborators to cease using a technology necessary to carry
out research, development and commercialization.

      Litigation to establish the validity of patents, to defend against patent
infringement claims of others and to assert infringement claims against others
can be expensive and time consuming, even if the outcome is favorable. An
outcome of any patent prosecution or litigation that is unfavorable to us, or
one of our licensors or collaborators, may have a material adverse effect on us.
We could incur substantial costs if we are required to defend ourselves in
patent suits brought by third parties, if we participate in patent suits brought
against or initiated by our licensors or collaborators or if we initiate such
suits. We may not have sufficient funds or resources in the event of litigation.
Additionally, we may not prevail in any such action.

      Any conflicts resulting from third-party patent applications and patents
could significantly reduce the coverage of the patents owned, optioned by or
licensed to us or our collaborators and limit our ability or that of our
collaborators to obtain meaningful patent protection. If patents are issued to
third parties that contain competitive or conflicting claims, we, our licensors
or our collaborators may be legally prohibited from pursuing research,
development or commercialization of potential products or be required to obtain
licenses to these patents or to develop or obtain alternative technology. We,
our licensors and/or our collaborators may be legally prohibited from using
patented technology, may not be able to obtain any license to the patents and
technologies of third parties on acceptable terms, if at all, or may not be able
to obtain or develop alternative technologies.

      In addition, like many biopharmaceutical companies, we may from time to
time hire scientific personnel formerly employed by other companies involved in
one or more areas similar to the activities conducted by us. We,


                                       6


or these individuals, may be subject to allegations of trade secret
misappropriation or other similar claims as a result of their prior
affiliations.

Our ability to compete may decrease if we do not adequately protect our
intellectual property rights.

      Our commercial success will depend in part on our and our collaborators'
ability to obtain and maintain patent protection for our proprietary
technologies, drug targets and potential products and to effectively preserve
our trade secrets. Because of the substantial length of time and expense
associated with bringing potential products through the development and
regulatory clearance processes to reach the marketplace, the pharmaceutical
industry places considerable importance on obtaining patent and trade secret
protection. The patent positions of pharmaceutical and biotechnology companies
can be highly uncertain and involve complex legal and factual questions. No
consistent policy regarding the breadth of claims allowed in biotechnology
patents has emerged to date. Accordingly, we cannot predict the type and breadth
of claims allowed in these patents.

      We also rely on copyright protection, trade secrets, know-how, continuing
technological innovation and licensing opportunities. In an effort to maintain
the confidentiality and ownership of trade secrets and proprietary information,
we require our employees, consultants and some collaborators to execute
confidentiality and invention assignment agreements upon commencement of a
relationship with us. These agreements may not provide meaningful protection for
our trade secrets, confidential information or inventions in the event of
unauthorized use or disclosure of such information, and adequate remedies may
not exist in the event of such unauthorized use or disclosure.

We depend on key employees in a competitive market for skilled personnel.

      We are highly dependent on the principal members of our management,
operations and scientific staff. The loss of any of their services would have a
material adverse effect on our business. We currently have employment agreements
with individuals who we consider to be "Key Employees." We do not maintain a key
person life insurance policy on the life of any employee.

      Our future success also will depend in part on the continued service of
our key scientific, bioinformatics and management personnel and our ability to
identify, hire and retain additional personnel, including, if required, customer
service, marketing and sales staff. We experience intense competition for
qualified personnel. We may not be able to continue to attract and retain
personnel necessary for the development of our business.

Our activities involve hazardous materials and may subject us to environmental
regulatory liabilities.

      Our biopharmaceutical research and development involves the controlled use
of hazardous and radioactive materials and biological waste. We are subject to
foreign, federal, state and local laws and regulations governing the use,
manufacture, storage, handling and disposal of these materials and certain waste
products. Although we believe that our safety procedures for handling and
disposing of these materials comply with legally prescribed standards, the risk
of accidental contamination or injury from these materials cannot be completely
eliminated. In the event of an accident, we could be held liable for damages,
and this liability could exceed our resources.

      We believe that we are in compliance in all material respects with
applicable environmental laws and regulations and currently do not expect to
make material additional capital expenditures for environmental control
facilities in the near term. However, we may have to incur significant costs to
comply with current or future environmental laws and regulations.

Our potential products may not be acceptable in the market or eligible for third
party reimbursement resulting in a negative impact on our future financial
results.

      Any products successfully developed by us or our collaborative partners
may not achieve market acceptance. The products we are attempting to develop
will compete with drugs manufactured and marketed by major pharmaceutical
companies. The degree of market acceptance of any of our products will depend on
a number of factors, including:


                                       7


      o     the establishment and demonstration in the medical community of the
            clinical efficacy and safety of such products,

      o     the potential advantage of such products over existing treatment
            methods, and

      o     reimbursement policies of government and third-party payors.

      Physicians, patients or the medical community in general may not accept or
utilize any products that may be developed by us, or our collaborative partners.
Our ability to receive revenues and income with respect to drugs, if any,
developed through the use of our technology will depend, in part, upon the
extent to which reimbursement for the cost of such drugs will be available from
third-party payers, such as government health administration authorities,
private health care insurers, health maintenance organizations, pharmacy
benefits management companies and other organizations. Third-party payers are
increasingly disputing the prices charged for pharmaceutical products. If
third-party reimbursement was not available or sufficient to allow profitable
price levels to be maintained for drugs developed by us, or our collaborative
partners, it could adversely affect our business.

If our products harm people, we may experience product liability claims that may
not be covered by insurance.

      We face an inherent business risk of exposure to potential product
liability claims in the event that drugs, if any, developed through the use of
our technology are alleged to have caused adverse effects on patients. Such risk
exists for products being tested in human clinical trials, as well as products
that receive regulatory approval for commercial sale. We may seek to obtain
product liability insurance with respect to drugs developed by us, and our
collaborative partners. However, we may not be able to obtain such insurance.
Even if such insurance is obtainable, it may not be available at a reasonable
cost or in a sufficient amount to protect us against liability.

We may be required to perform additional clinical trials or change the labeling
of our products if we, or others, identify side effects after our products are
on the market, which could harm sales of the affected products.

      If we, or others, identify side effects after any of our products, if any,
after they are on the market, or if manufacturing problems occur,

      o     regulatory approval may be withdrawn;

      o     reformulation of our products, additional clinical trials, changes
            in labeling of our products may be required;

      o     changes to or re-approvals of our manufacturing facilities may be
            required;

      o     sales of the affected products may drop significantly;

      o     our reputation in the marketplace may suffer; and/or

      o     lawsuits, including class action suits, may be brought against us.

      Any of the above occurrences could harm or prevent sales of the affected
products or could increase the costs and expenses of commercializing and
marketing these products.

Health care reform and controls on health care spending may limit the price we
charge for any products and the amounts thereof that we can sell.

      The U.S. federal government and private insurers have considered ways to
change, and have changed, the manner in which health care services are provided
in the U.S. Potential approaches and changes in recent years include controls on
health care spending and the creation of large purchasing groups. In the future,
the U.S.


                                       8


government may institute further controls and limits on Medicare and Medicaid
spending. These controls and limits might affect the payments we could collect
from sales of any products. Uncertainties regarding future health care reform
and private market practices could adversely affect our ability to sell any
products profitably in the U.S.

The manufacture of commensal bacteria is a time-consuming and complex process.

      Our management believes that we have the ability to acquire or produce
quantities of commensal bacteria sufficient to support our present needs for
research and our projected needs for our initial clinical development programs.
However, we believe that improvements in our manufacturing technology will be
required to enable us to meet the volume and cost requirements needed for
certain commercial applications of commensal products. We may not be able to
obtain sufficient funds to make such improvements. Products based on commensals
have never been manufactured on a commercial scale. The manufacture of all of
our products will be subject to current Good Manufacturing Practices or "GMP,"
requirements prescribed by the FDA or other standards prescribed by the
appropriate regulatory agency in the country of use. There can be no assurance
that we will be able to manufacture products, or have products manufactured for
us, in a timely fashion at acceptable quality and prices, that they or third
party manufacturers can comply with GMP or that we or third party manufacturers
will be able to manufacture an adequate supply of product.

The future issuance of preferred stock may adversely affect the rights of the
holders of our common stock.

      Our certificate of incorporation allows our Board of Directors to issue up
to 10,000,000 shares of preferred stock and to fix the voting powers,
designations, preferences, rights and qualifications, limitations or
restrictions of these shares without any further vote or action by the
stockholders. The rights of the holders of common stock will be subject to, and
could be adversely affected by, the rights of the holders of any preferred stock
that we may issue in the future. The issuance of preferred stock, while
providing desirable flexibility in connection with possible acquisitions and
other corporate purposes, could have the effect of making it more difficult for
a third party to acquire a majority of our outstanding voting stock, thereby
delaying, deferring or preventing a change in control.

Concentration of ownership of our capital stock could delay or prevent a change
of control.

      Our directors, executive officers and principal stockholders beneficially
own a significant percentage of our outstanding common stock and preferred
stock. They also have, through the exercise or conversion of certain securities,
the right to acquire additional common stock. As a result, these stockholders,
if acting together, have the ability to significantly influence the outcome of
corporate actions requiring stockholder approval. Additionally, this
concentration of ownership may have the effect of delaying or preventing a
change in control of SIGA.

                                 USE OF PROCEEDS

      The net proceeds from the sale of the shares of common stock offered will
be received by the selling stockholders. We will not receive any of the proceeds
from the sale of the shares of common stock offered by the selling stockholders
but we will receive proceeds from the exercise of the warrants held by the
selling stockholders. We will use proceeds from the exercise of warrants as
general working capital.

                              SELLING STOCKHOLDERS

      The table below sets forth information regarding ownership of our common
stock by the selling stockholders on January 16, 2003 and the shares of common
stock to be sold by them under this prospectus. Beneficial ownership is
determined in accordance with SEC rules and includes voting or investment power
with respect to the securities. Except as indicated by footnote, and subject to
applicable community property laws, the persons named in the table have sole
voting and investment power with respect to all shares of common stock shown as
beneficially owned by them. SEC rules require that the number of shares of
common stock outstanding used in calculating the percentage for each listed
person includes the shares of common stock underlying warrants or options held
by such person that are exercisable within 60 days of January 16, 2003. As of
January 16, 2003, 13,226,649 shares of common stock were outstanding.


                                       9




                                                       Securities Owned Prior to Offering            Securities Owned After Offering
                                                                                                        Number of
                                                                   Percent of      Shares of           Shares of         Percent of
                                                Shares of            Common      Common Stock            Common            Common
        Name of Selling Stockholder           Common Stock           Stock      Offered Hereby           Stock             Stock
        ---------------------------           ------------           -----      --------------           -----             -----
                                                                                                                 
Murray Alon                                       50,000                  *         50,000                  0                  *
Leonard Cohen                                     25,000                  *         25,000                  0                  *
Marvin Sheeber                                    50,000                  *         50,000                  0                  *
Ronald Schaffer                                   25,000                  *         25,000                  0                  *
Robert Walker                                     12,500                  *         12,500                  0                  *
Jerome Belson                                     50,000                  *         50,000                  0                  *
Robert Karsten, DDS                               50,000                  *         50,000                  0                  *
Guy Michael Dart                                  50,000                  *         50,000                  0                  *
Jeanette Dart                                     12,500                  *         12,500                  0                  *
Robert M. Rosenblum                               25,000                  *         25,000                  0                  *
Gerald Brauser                                   100,000                  *        100,000                  0                  *
Maximillian Santos                                22,727                  *         22,727                  0                  *
Bruce B. Federman                                 25,000                  *         25,000                  0                  *
Leo Berman                                        18,750(1)               *         18,750(1)               0                  *
E. Gerald Kay                                     75,000(2)               *         75,000(2)               0                  *
Delores Bowman                                    87,500(3)               *         87,500(3)               0                  *
C. Ames Byrd & Donna Byrd
JTWROS                                            75,000(2)               *         75,000(2)               0                  *
Paul Becker                                      150,000(4)            1.10%       150,000(4)               0                  *
Kevin Hurley                                      75,000(2)               *         75,000(2)               0                  *
Dennis Levine                                     62,500(3)               *         62,500(3)               0                  *
Urs Brunner                                      150,000(4)            1.10%       150,000(4)               0                  *
Lance Investments Holdings Ltd.                  150,000(4)            1.10%       150,000(4)               0                  *
Henderson Orthopedics Profit Sharing Plan         37,500(3)               *         37,500(3)               0                  *
Kenneth Wilk                                      64,773(3)               *         64,773(3)               0                  *
Tis Prager                                        75,000(2)               *         75,000(2)               0                  *
Keys Foundation                                  112,500(5)               *        112,500(5)               0                  *
Israel Cohen                                      75,000(2)               *         75,000(2)               0                  *
Lindsay E. Dart                                   75,000(2)               *         75,000(2)               0                  *
Joseph Giamanco                                  150,000(4)            1.10%       150,000(4)               0                  *
Warren Gilbert & Marianne Gilbert
JT IN THE ENTIRETY                                37,500(3)               *         37,500(3)               0                  *
Bruno Widmer                                      37,500(3)               *         37,500(3)               0                  *
Harold Miller                                     31,250(1)               *         31,250(1)               0                  *
Daniel Orenstein                                  31,250(1)               *         31,250(1)               0                  *
Frank Lagano                                      62,500(3)               *         62,500(3)               0                  *
Ronald J. Menello                                 75,000(2)               *         75,000(2)               0                  *
Bridge Ventures, Inc.                            300,000(6)             2.2%       300,000(6)               0                  *
Langley Partners                                 366,667(7)             2.7%       300,000             66,667(7)               *
Gryphpon Master Fund, L.P.                       500,000(8)             3.6%       400,000            100,000(8)               *
Cranshire Capital                                408,333(9)             3.0%       200,000            208,333(9)             1.6%
Alfons Melohn                                    343,478(10)              *        100,000            243,478(10)            1.8%
First Montauk                                     26,736(11)              *         26,736(11)              0                  *
Christine Walker                                   3,176(12)              *          3,176(12)              0                  *
Kevin J. Martin                                   74,169(13)              *         74,169(13)              0                  *
Daniel Walsh                                      74,169(13)              *         74,169(13)              0                  *
Michael Jacks                                     10,000(14)              *         10,000(14)              0                  *
Gary J. Shemano                                   40,000(15)              *         40,000(15)              0                  *
Willaim Corbett                                   40,000(15)              *         40,000(15)              0                  *
Scarborough, Ltd.                                 10,228(16)              *         10,228(16)              0                  *
The Promotion Factory                             65,000(17)              *         65,000(17)              0                  *
Bridington Ltd.                                   65,000(17)              *         65,000(18)              0                  *



                                       10


----------
*     Less than one percent

      (1)   Includes 6,250 shares of common stock issuable upon exercises of
            warrants.

      (2)   Includes 25,000 shares of common stock issuable upon exercises of
            warrants.

      (3)   Includes 12,500 shares of common stock issuable upon exercises of
            warrants.

      (4)   Includes 50,000 shares of common stock issuable upon exercises of
            warrants.

      (5)   Includes 37,500 shares of common stock issuable upon exercises of
            warrants.

      (6)   Includes 250,000 shares of common stock issuable upon exercises of
            warrants.

      (7)   Includes 66,667 shares of common stock issuable upon exercises of
            warrants.

      (8)   Includes 100,000 shares of common stock issuable upon exercises of
            warrants.

      (9)   Includes 208,333 shares of common stock issuable upon exercises of
            warrants.

      (10)  Includes 240,478 shares of common stock issuable upon exercises of
            warrants.

      (11)  Includes 26,736 shares of common stock issuable upon exercise of
            warrants.

      (12)  Includes 3,176 shares of common stock issuable upon exercises of
            warrants.

      (13)  Includes 74,169 shares of common stock issuable upon exercises of
            warrants.

      (14)  Includes 10,000 shares of common stock issuable upon exercises of
            warrants.

      (15)  Includes 40,000 shares of common stock issuable upon exercises of
            warrants.

      (16)  Includes 10,228 shares of common stock issuable upon exercises of
            warrants.

      (17)  Includes 65,000 shares of common stock issuable upon exercises of
            options.

      The information provided in the table above with respect to the selling
stockholders has been obtained from such selling stockholders.

      Except as otherwise disclosed above or in documents incorporated herein by
reference, the selling stockholders, have not within the past three years had
any position, office or other material relationship with us or any of our
predecessors or affiliates. Because the selling stockholders may sell all or
some portion of the shares of common stock beneficially owned by them, only an
estimate (assuming the selling stockholders sell all of the shares offered
hereby) can be given as to the number of shares of common stock that will be
beneficially owned by the selling stockholders after this offering. In addition,
the selling stockholders may have sold, transferred or otherwise disposed of, or
may sell, transfer or otherwise dispose of, at any time or from time to time
since the dates on which they provided the information regarding the shares
beneficially owned by them, all or a portion of the shares beneficially owned by
them in transactions exempt from the registration requirements of the Securities
Act.

      We have filed with the SEC, under the Securities Act of 1933, a
registration statement on Form S-3, of which this prospectus forms a part, with
respect to the resale of the securities from time to time on the Nasdaq SmallCap
Market or in privately-negotiated transactions and have agreed to prepare and
file such amendments and supplements to the registration statement as may be
necessary to keep the registration statement effective until the earlier of (i)
February 14, 2006, (ii) the date when the selling stockholders may sell all of
the shares of common stock under Rule 144 without volume or other restrictions
or limits, or (iii) the date on which the selling stockholders have sold all of
the shares of common stock.

                              PLAN OF DISTRIBUTION

      This prospectus covers the sale of shares of common stock from time to
time by the selling stockholders named in the table above. The selling
stockholders will act independently of us in making decisions with respect to
the timing, manner and size of each sale. The sales may be made on one or more
exchanges or in the over-the-


                                       11


counter market or otherwise, at prices and at terms then prevailing or at prices
related to the then current market price, or in negotiated transactions. The
selling stockholders may effect such transactions by selling the shares to or
through broker-dealers. The shares may be sold by one or more of, or a
combination of, the following:

      o     a block trade in which the broker-dealer so engaged will attempt to
            sell the shares as agent but may position and resell a portion of
            the block as principal to facilitate the transaction;

      o     purchases by a broker-dealer as principal and resale by such
            broker-dealer for its account pursuant to this prospectus;

      o     an exchange distribution in accordance with the rules of such
            exchange;

      o     ordinary brokerage transactions and transactions in which the broker
            solicits purchasers; and

      o     in privately negotiated transactions.

      To the extent required, this prospectus may be amended or supplemented
from time to time to describe a specific plan of distribution. In effecting
sales, broker-dealers engaged by the selling stockholder may arrange for other
broker-dealers to participate in the resales.

      The selling stockholders may enter into hedging transactions with
broker-dealers in connection with distributions of the shares or otherwise. In
such transactions, broker-dealers may engage in short sales of the shares in the
course of hedging the positions they assume with the selling stockholders. The
selling stockholders also may sell shares short and redeliver the shares to
close out such short positions. The selling stockholders may enter into option
or other transactions with broker-dealers which require the delivery to the
broker-dealer of the shares. The broker-dealer may then resell or otherwise
transfer such shares pursuant to this prospectus.

      The selling stockholders also may loan or pledge the shares to a
broker-dealer. The broker-dealer may sell the shares so loaned, or upon a
default the broker-dealer may sell the pledged shares pursuant to this
prospectus. Broker-dealers or agents may receive compensation in the form of
commissions, discounts or concessions from the selling stockholders.
Broker-dealers or agents may also receive compensation from the purchasers of
the shares for whom they act as agents or to whom they sell as principals, or
both. Compensation as to a particular broker-dealer might be in excess of
customary commissions and will be in amounts to be negotiated in connection with
the sale. Broker-dealers or agents and any other participating broker-dealers or
the selling stockholders may be deemed to be "underwriters" within the meaning
of Section 2(11) of the Securities Act in connection with sales of the shares.
Accordingly, any such commission, discount or concession received by them and
any profit on the resale of the shares purchased by them may be deemed to be
underwriting discounts or commissions under the Securities Act. Because the
selling stockholders may be deemed to be "underwriters" within the meaning of
Section 2(11) of the Securities Act, the selling stockholders will be subject to
the prospectus delivery requirements of the Securities Act. In addition, any
securities covered by this prospectus which qualify for sale pursuant to Rule
144 promulgated under the Securities Act may be sold under Rule 144 rather than
pursuant to this prospectus. The selling stockholders have advised us that they
have not entered into any agreements, understandings or arrangements with any
underwriters or broker-dealers regarding the sale of their securities. There is
no underwriter or coordinating broker acting in connection with the proposed
sale of shares by the selling stockholders.

      The shares will be sold only through registered or licensed brokers or
dealers if required under applicable state securities laws. In addition, in
certain states the shares may not be sold unless they have been registered or
qualified for sale in the applicable state or an exemption from the registration
or qualification requirement is available and is complied with.

      Under applicable rules and regulations under the Exchange Act, any person
engaged in the distribution of the shares may not simultaneously engage in
market making activities with respect to our common stock for a period of two
business days prior to the commencement of such distribution. In addition, the
selling stockholders will be subject to applicable provisions of the Exchange
Act and the associated rules and regulations under the Exchange Act, including
Regulation M, which provisions may limit the timing of purchases and sales of
shares of our common


                                       12


stock by the selling stockholders. We will make copies of this prospectus
available to the selling stockholders and have informed them of the need for
delivery of copies of this prospectus to purchasers at or prior to the time of
any sale of the shares.

      We will file a supplement to this prospectus, if required, pursuant to
Rule 424(b) under the Securities Act upon being notified by the selling
stockholders that any material arrangement has been entered into with a
broker-dealer for the sale of shares through a block trade, special offering,
exchange distribution or secondary distribution or a purchase by a broker or
dealer. Such supplement will disclose:

      o     the name of the selling stockholder and of the participating
            broker-dealer(s);

      o     the number of shares involved;

      o     the price at which such shares were sold;

      o     the commissions paid or discounts or concessions allowed to such
            broker-dealer(s), where applicable;

      o     that such broker-dealer(s) did not conduct any investigation to
            verify the information set out or incorporated by reference in this
            prospectus; and

      o     other facts material to the transaction.

      We will bear all costs, expenses and fees in connection with the
registration of the shares. The selling stockholders will bear all commissions
and discounts, if any, attributable to the sales of the shares. We have agreed
to indemnify certain selling stockholders against certain liabilities, including
liabilities under the Securities Act in connection with the offering of the
shares or to contribute to payments which such selling stockholders may be
required to make in respect thereof. The selling stockholders may agree to
indemnify certain persons, including broker-dealers and agents, against certain
liabilities in connection with the offering of the shares, including liabilities
arising under the Securities Act.

                                  LEGAL MATTERS

      The validity of the shares of common stock offered hereby will be passed
upon for SIGA by Kramer Levin Naftalis & Frankel LLP.

                                     EXPERTS

      The financial statements incorporated in this prospectus by reference to
the Annual Report on Form 10-KSB for the year ended December 31, 2001 have been
so incorporated in reliance on the report of PricewaterhouseCoopers LLP,
independent accountants, given on the authority of said firm as experts in
auditing and accounting.

     COMMISSION'S POSITION ON INDEMNIFICATION FOR SECURITIES ACT LIABILITIES

      In the opinion of the Securities and Exchange Commission, or "Commission,"
indemnification for certain acts of directors, officers and controlling persons
is against public policy, as expressed in the Securities Act, and is, therefore,
unenforceable. If a claim for indemnification against such liabilities (other
than the payment by us of expenses incurred or paid by a director, officer or
controlling person of SIGA in the successful defense of any action, suit or
proceeding) is asserted by any SIGA director, officer or controlling person in
connection with the securities being registered, we will, unless in the opinion
of our counsel the matter has been settled by controlling precedent, submit to a
court of appropriate jurisdiction the question whether such indemnification by
SIGA is against public policy as expressed in the Securities Act and will be
governed by the final adjudication of that issue.


                                       13


                             ADDITIONAL INFORMATION

      We have filed a registration statement on Form S-3 with the Commission
relating to the common stock offered by this prospectus. This prospectus does
not contain all of the information set forth in the registration statement and
the exhibits and schedules to the registration statement. Statements contained
in this prospectus concerning the contents of any contract or other document
referred to are not necessarily complete and in each instance we refer you to
the copy of the contract or other document filed as an exhibit to the
registration statement, each such statement being qualified in all respects by
such reference.

      For further information with respect to us and the common stock being
offered, please refer to the registration statement. A copy of the registration
statement can be inspected by anyone without charge at the public reference room
of the Commission, Room 1024, 450 Fifth Street, N.W., Washington, D.C. 20549,
and at the Commission's Regional Offices located at 233 Broadway, New York, New
York 10279, and 500 West Madison Street, Chicago, Illinois 60601. Please call
the Commission at 1-800-SEC-0330 for further information on the operation of the
public reference room. Copies of these materials can be obtained by mail from
the Public Reference Section of the Commission at 450 Fifth Street, N.W.,
Washington, D.C. 20549, at prescribed rates. The Commission maintains a Web site
(http://www.sec.gov) that contains information regarding registrants that file
electronically with the Commission.

                           INCORPORATION BY REFERENCE

      Incorporated by reference into this prospectus is the information set
forth in the following documents:

      o     our Annual Report on Form 10-KSB for the year ended December 31,
            2001;

      o     the description of our common stock contained in our registration
            statement on Form 8-A under Section 12 of the Exchange Act, dated
            September 5, 1997, including any amendment or reports filed for the
            purpose of updating such description;

      o     our quarterly reports on Form 10-QSB for the quarters ended March
            31, 2002, June 30, 2002 and September 30, 2002; and

      o     our current reports on Form 8-K filed on March 20, 2002, October 10,
            2002 and January 14, 2003.

      We will furnish to any person to whom this prospectus is delivered,
without charge, a copy of these documents upon written or oral request to Thomas
N. Konatich, Acting Chief Executive Officer and Chief Financial Officer, 420
Lexington Avenue, Suite 601, New York, New York 10170, tel. (212) 672-9100.


                                       14


                                     PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

Item 14. Other Expenses of Issuance and Distribution.

      The following table sets forth the estimated costs and expenses of the
sale and distribution of the securities being registered, all of which are being
borne by us.

                                                                     Amount
                                                                     ------
      SEC filing fee ........................................     $   435.37
      Printing expenses .....................................       2,000.00
      Legal Fees and Expenses ...............................      15,000.00
      Accounting Fees and Expenses ..........................       5,000.00
      Miscellaneous .........................................          64.63

              Total .........................................     $22,500.00

      All of the amounts shown are estimates except for the fee payable to the
SEC.

Item 15. Indemnification of Directors and Officers

      Section 145 of the Delaware General Corporation Law provides that a
corporation may indemnify directors and officers, as well as other employees and
individuals, against expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement actually and reasonably incurred by any such person
in connection with any threatened, pending or completed actions, suits or
proceedings in which such person is made a party by reason of such person being
or having been a director, officer, employee or agent to the Registrant. The
Delaware General Corporation Law provides that Section 145 is not exclusive of
other rights to which those seeking indemnification may be entitled under any
bylaw, agreement, vote of stockholders or disinterested directors or otherwise.
Article IX of the Registrant's Certificate of Incorporation and Article VII of
the Registrant's Bylaws provides for indemnification by the Registrant of its
directors and officers to the fullest extent permitted by the Delaware General
Corporation Law.

      Section 102(b)(7) of the Delaware General Corporation Law permits a
corporation to provide in its certificate of incorporation that a director of
the corporation shall not be personally liable to the corporation or its
stockholders for monetary damages for breach of fiduciary duty as a director,
except for liability (i) for any breach of the director's duty of loyalty to the
corporation or its stockholders, (ii) for acts or omissions not in good faith or
which involve intentional misconduct or a knowing violation of law, (iii) for
unlawful payments of dividends or unlawful stock repurchases, redemptions or
other distributions, or (iv) for any transaction from which the director derived
an improper personal benefit. The Registrant's Certificate of Incorporation
provides for such limitation of liability.


                                      II-1


Item 16. Exhibits

Exhibit No.     Description
-----------     -----------

5.1*            Opinion of Kramer Levin Naftalis & Frankel LLP.

23.1**          Consent of PricewaterhouseCoopers LLP.

23.2*           Consent of Kramer Levin Naftalis & Frankel LLP (contained in the
                opinion filed as Exhibit 5.1 hereto).

24.1**          Power of Attorney (contained on the signature page of this
                Registration Statement).

----------
*  To be filed by amendment

** Filed herewith

Item 17. Undertakings

      The undersigned registrant hereby undertakes:

      (1) to file, during any period in which offers or sale; are being made, a
post-effective amendment to this registration statement:

            (i) to include any prospectus required by Section 10(a)(3) of the
      Securities Act of 1933;

            (ii) to reflect in the prospectus any facts or events arising after
      the effective date of the registration statement (or the most recent
      post-effective amendment thereof) which, individually or in the aggregate,
      represent a fundamental change in the information set forth in the
      registration statement. Notwithstanding the foregoing, any increase or
      decrease in volume of securities offered (if the total dollar value of
      securities offered would not exceed that which was registered) and any
      deviation from the low or high end of the estimated maximum offering range
      may be reflected in the form of prospectus filed with the Commission
      pursuant to Rule 424(b) if, in the aggregate, the changes in volume and
      price represent no more than a 20% change in the maximum aggregate
      offering price set forth in the "Calculation of Registration Fee" table in
      the effective registration statement.

            (iii) to include any material information with respect to the plan
      of distribution not previously disclosed in the registration statement or
      any material change to such information in the registration statement;
      provided, however, that paragraphs (1)(i) and (1)(ii) above do not apply
      if the registration statement is on Form S-3, and the information required
      to be, included in a post-effective amendment by those paragraphs is
      contained in periodic reports filed by the registrant pursuant to Section
      13 or Section 15(d) of the Securities Exchange Act of 1934 that are
      incorporated by reference in the registration statement.

      (2) That, for the purpose of determining any liability under the
Securities Act of 1933, each such post-effective amendment shall be deemed to be
a new registration statement relating to the securities offered therein, and the
offering of such securities at the time shall be deemed to be the initial bona
fide offering thereof.

      (3) To remove from registration by means of a post-effective amendment any
of the securities being registered which remain unsold at the termination of the
offering.

      The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act of 1933, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Securities Exchange Act of 1934 (and, where applicable, each filing of an
employee benefit plan's annual report pursuant to Section 15(d) of the
Securities Exchange Act of 1934) that is incorporated by reference in the


                                      II-2


registration statement shall be deemed to be a new registration relating to the
securities offered herein, and the offering of such securities at that time
shall be deemed to be the initial bona fide offering thereof.

      The undersigned registrant hereby undertakes to deliver or cause to be
delivered with the prospectus, to each person to whom the prospectus is sent or
given, the latest annual report, to security holders that is incorporated by
reference in the prospectus and furnished pursuant to and meeting the
requirements of Rule 14a-3 or Rule 14c-3 under the Securities Exchange Act of
1934; and, where interim financial information required to be presented by
Article 3 of Regulation S-X is not set forth in the prospectus, to deliver, or
cause to be delivered to each person to whom the prospectus is sent or given,
the latest quarterly report that is specifically incorporated by reference in
the prospectus to provide such interim financial information.

      Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors, officers and controlling persons of
the registrant pursuant to the foregoing provisions, or otherwise, the
registrant has been advised that in the opinion of the Securities and Exchange
Commission such indemnification is against public policy as expressed in the Act
and is, therefore, unenforceable. In the event that a claim for indemnification
against such liabilities (other than payment by the registrant of expenses
incurred or paid by a director, officer or controlling person of the registrant
in the successful defense of any action, suit or proceeding) is asserted by such
director, officer or controlling person in connection with the securities being
registered, the registrant will, unless in the opinion of its counsel the matter
has been settled by controlling precedent, submit to a court of appropriate
jurisdiction the question whether such indemnification by the final adjudication
of such issue.


                                      II-3


                                   SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, SIGA
Technologies, Inc. certifies that it has reasonable grounds to believe that it
meets all of the requirements for filing on Form S-3 and has duly caused this
registration statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of New York, New York on February 14, 2003.

                                       SIGA Technologies, Inc.


                                       By: /s/ Thomas N. Konatich
                                           -------------------------------------
                                           Thomas N. Konatich
                                           Acting Chief Executive Officer

      KNOW ALL PERSONS BY THESE PRESENTS, that the persons whose signatures
appear below each severally constitutes and appoints Thomas N. Konatich and
Donald G. Drapkin his true and lawful attorneys-in-fact and agents, with full
powers of substitution and resubstitution, for him and in his name, place and
stead, in any and all capacities, to sign any and all amendments (including
pre-effective and post-effective amendments) to this registration statement and
to sign any registration statement (and any post-effective amendments) relating
to the same offering as this registration statement that is to be effective upon
filing pursuant to Rule 462(b) under the Securities Act of 1933, and to file the
same, with all exhibits, and other documents in connection therewith, with the
Securities and Exchange Commission, granting unto said attorneys-in-fact and
agents, full power and authority to do and perform each and every act and thing
requisite and necessary to be done in and about the premises, as fully to all
intents and purposes as he might or could do in person, hereby ratifying and
confirming all which said attorneys-in-fact and agents, or their substitute, may
lawfully do, or cause to be done by virtue hereof.

      Pursuant to the requirements of the Securities Act of 1933, as amended,
this registration statement has been signed below by the following persons in
the capacities and on the dates indicated.

       Signature                  Title of Capacities                 Date
       ---------                  -------------------                 ----

/s/ Thomas N. Konatich      Acting Chief Executive Officer     February 14, 2003
------------------------     and Chief Financial Officer

/s/ Donald G. Drapkin       Chairman of the Board              February 14, 2003
------------------------

/s/ Eric A. Rose, M.D.      Director                           February 14, 2003
------------------------

/s/ Gabriel M. Cerrone      Director                           February 14, 2003
------------------------

/s/ Thomas E. Constance     Director                           February 14, 2003
------------------------

/s/ Mehmet C. Oz, M.D.      Director                           February 14, 2003
------------------------

/s/ Michael Weiner, M.D.    Director                           February 14, 2003
------------------------


                                      II-4


                                  EXHIBIT INDEX

Exhibit No.   Description
-----------   -----------

5.1*          Opinion of Kramer Levin Naftalis & Frankel LLP.

23.1**        Consent of PricewaterhouseCoopers LLP.

23.2*         Consent of Kramer Levin Naftalis & Frankel LLP (contained in the
              opinion filed as Exhibit 5.1 hereto).

24.1**        Power of Attorney (contained on the signature page of this
              Registration Statement).

----------
*  To be filed by amendment

** Filed herewith


                                      II-5