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                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
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                                  SCHEDULE 13D

                    Information to be Included in Statements
                       Filed Pursuant to Rule 13d-1(a) and
               Amendments Thereto Filed pursuant to Rule 13d-2(a)
                                (Amendment No. 6)
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                         Barrett Business Services, Inc.
                                (Name of Issuer)
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                          Common Stock, $.01 par value
                         (Title of Class of Securities)
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                                   068463 10 8
                                 (CUSIP Number)
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                               William W. Sherertz
                         Barrett Business Services, Inc.
                            4724 S.W. Macadam Avenue
                             Portland, Oregon 97239
                            Telephone: (503) 220-0988
            (Name, Address, and Telephone Number of Person Authorized
                     to Receive Notices and Communications)

                                    Copy to:

                                 Mary Ann Frantz
                                 Miller Nash LLP
                        111 S.W. Fifth Avenue, Suite 3400
                             Portland, Oregon 97204
                            Telephone: (503) 224-5858

                                   May 7, 2004
             (Date of Event which Requires Filing of this Statement)

If the filing person has previously  filed a statement on Schedule 13G to report
the  acquisition  that is the subject of this  Schedule  13D, and is filing this
schedule because of Rule 13d-1(e), 13d-1(f) or 13d-1(g), check the following box
[ ].
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CUSIP 068463 10 8                                            Page 2 of 6 pages
                                       13D

1.    Names of Reporting Persons

      I.R.S. Identification Nos. of Above Persons (Entities Only)

      William W. Sherertz

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2.    Check the Appropriate Box if a Member of a Group
      [  ]  (a)
      [  ]  (b)

3.    SEC Use Only

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4.    Source of Funds

      PF, BK

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5.    [  ]  Check Box if Disclosure of Legal Proceedings is
              Required Pursuant to Item 2(d) or 2(e)

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6.    Citizenship or Place of Organization

      United States

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Number of Shares Beneficially Owned by Each Reporting Person With:

7.    Sole Voting Power

      1,899,657

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8.    Shared Voting Power

      41,300

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9.    Sole Dispositive Power

      1,899,657

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10.   Shared Dispositive Power

      41,300

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11.   Aggregate Amount Beneficially Owned by Each Reporting Person

      1,940,957

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CUSIP 068463 10 8                                            Page 3 of 6 pages

12.   [  ]  Check Box if the Aggregate Amount in Row 11 Excludes
              Certain Shares

13.   Percent of Class Represented by Amount in Row 11

      33.8 percent

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14.   Type of Reporting Person

      IN

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CUSIP 068463 10 8                                            Page 4 of 6 pages

Item 1.  Security and Issuer.

      The title of the class of equity  securities to which this Amendment No. 6
to statement on Schedule 13D (this  "Statement")  relates is common stock,  $.01
par value  ("Common  Stock"),  of Barrett  Business  Services,  Inc., a Maryland
corporation (the "Company").  The address of the Company's  principal  executive
offices is 4724 S.W. Macadam Avenue, Portland, Oregon 97239.

Item 2.  Identity and Background.

      (a)-(c), (f)  This  statement  is  filed  by  William  W.  Sherertz  ("Mr.
Sherertz"), whose business address is 4724 S.W. Macadam Avenue, Portland, Oregon
97239.  Mr.  Sherertz's  present  principal  occupation  is President  and Chief
Executive  Officer of the Company.  The Company is a human  resource  management
company engaged in providing  staffing and professional  employer  services to a
diversified  group of customers  through a network of 28 branch offices in eight
states.  The Company's address is set forth in Item 1. Mr. Sherertz is a citizen
of the United States.

      (d)-(e)  During  the  last  five  years,  Mr.  Sherertz  has not (i)  been
convicted in a criminal  proceeding  (excluding  traffic  violations  or similar
misdemeanors)  or (ii)  been a party  to a civil  proceeding  of a  judicial  or
administrative body of competent jurisdiction and as a result of such proceeding
was or is  subject  to a  judgment,  decree  or  final  order  enjoining  future
violations  of, or prohibiting  or mandating  activities  subject to, federal or
state securities laws or finding any violation with respect to such laws.

Item 3.  Source and Amount of Funds or Other Consideration.

      Since October 9, 2001, the filing date of Amendment No. 5 to the statement
on Schedule 13D filed by Mr. Sherertz ("Amendment No. 5"), he has:

            (a)   Sold a total of 214,000  shares of Common  Stock in seven open
      market   transactions   for  a  total  purchase  price  of   approximately
      $1,389,300; and

            (b)   Exercised  employee stock options for a total of 66,719 shares
      of Common Stock through the delivery of a total of 24,743 shares of Common
      Stock in payment  of the  exercise  price,  for a net  increase  of 41,976
      shares.

      The  source  and  amount of funds or other  consideration  used to acquire
Common  Stock prior to filing of  Amendment  No. 5 were  previously  reported in
Amendment No. 5.

Item 4.  Purpose of Transaction.

      Mr.  Sherertz  acquires or disposes of shares of Common Stock from time to
time for  personal  reasons.  Except in the  ordinary  course of Mr.  Sherertz's
management  of the Company in his  capacity  as  President  and Chief  Executive
Officer, Mr. Sherertz has no present plans or proposals which relate to or would
result in:

            (a)   The acquisition by any person of additional  securities of the
      Company other than grants to and exercises of employee  stock options held
      by Mr. Sherertz from



CUSIP 068463 10 8                                            Page 5 of 6 pages

      time to time, or the  disposition  of securities of the Company other than
      by  gift  undertaken  by Mr.  Sherertz  for  charitable  or  tax  planning
      purposes;

            (b)   An  extraordinary  corporate  transaction,  such as a  merger,
      reorganization  or  liquidation,  involving  the  Company  or  any  of its
      subsidiaries;

            (c)   A sale or  transfer  of a  material  amount  of  assets of the
      Company or any of its subsidiaries;

            (d)   Any change in the present  board of directors or management of
      the Company, including any plans or proposals to change the number or term
      of directors or to fill any existing vacancies on the board;

            (e)   Any material change in the present  capitalization or dividend
      policy of the Company;

            (f)   Any  other  material  change  in  the  Company's  business  or
      corporate structure;

            (g)   Changes  in  the  Company's  charter,  bylaws  or  instruments
      corresponding thereto or other actions which may impede the acquisition of
      control of the Company by any person;

            (h)   Causing a class of  securities  of the  Company to be delisted
      from a national  securities  exchange or to cease to be  authorized  to be
      quoted  in an  inter-dealer  quotation  system  of a  registered  national
      securities association;

            (i)   A class of equity  securities of the Company becoming eligible
      for  termination  of  registration  pursuant  to Section  12(g)(4)  of the
      Securities Exchange Act of 1934; or

            (j)   Any action similar to any of those enumerated above.

Item 5.  Interest in Securities of the Issuer.

      (a)-(b) Mr. Sherertz beneficially owns 1,940,957 shares of Common Stock or
33.8 percent of the  outstanding  Common Stock.  Mr.  Sherertz has sole power to
vote and sole power to dispose of 1,899,657 shares, which includes 38,024 shares
subject to options that are  presently  exercisable  or will become  exercisable
within 60 days of the date of this Statement.  In addition,  Mr. Sherertz shares
voting and  dispositive  powers as to 10,000  shares held by his wife and 31,300
shares held by Mr. Sherertz for his minor children.

      (c)  During  the  past  60  days,  Mr.  Sherertz  has not  engaged  in any
transactions in the Common Stock.

      (d)-(e) Not applicable.



CUSIP 068463 10 8                                            Page 6 of 6 pages

Item 6. Contracts, Arrangements, Understandings or Relationships with Respect to
Securities of the Issuer.

      Mr. Sherertz entered into a letter  agreement,  dated August 17, 1992 (the
"Agreement"),  with Nancy B.  Sherertz  pursuant  to which they agreed to divide
their  holdings  of  Company  capital  stock  equally  upon  the  closing  of an
underwriting  agreement for an initial public offering of Company capital stock.
The Agreement was entered into by Ms. Sherertz for personal reasons based on her
then  marital   relationship  with  Mr.  Sherertz  and  also  to  recognize  his
contribution  to the  Company's  growth and his  efforts to  establish  a public
market for the Common Stock.  The  Agreement  was fully  performed in connection
with  the  Company's  initial  public  offering  in June  1993.  Except  for the
Agreement and award agreements for employee stock options in  substantially  the
form referred to in Item 7, there are no contracts, arrangements, understandings
or relationships  (legal or otherwise) between Mr. Sherertz and any other person
with  respect to any  securities  of the Company,  including  but not limited to
transfer or voting of any of the securities, finders' fees, joint ventures, loan
or option  arrangements,  puts or calls,  guarantees  of  profits,  division  of
profits or loss, or the giving or withholding of proxies.

Item 7.  Material to be Filed as Exhibits.

            (a)   Letter  agreement  between  Nancy B.  Sherertz  and William W.
      Sherertz dated August 17, 1992. (Incorporated by reference to Exhibit 10.6
      to the  Company's  registration  statement  on  Form  S-1  (No.  33-61804)
      effective June 11, 1993.)

            (b)   Form  of  Nonqualified   Stock  Option   Agreement  under  the
      Company's 2003 Stock Incentive Plan. (Incorporated by reference to Exhibit
      10.12 to the  Company's  annual  report  on Form  10-K for the year  ended
      December 31, 2003.)*

___________

      * Individual  agreements  representing grants of employee stock options to
Mr.  Sherertz  are  substantially  identical  to Exhibit (b) except for exercise
price and dates of vesting and expiration.

                                    SIGNATURE

      After  reasonable  inquiry and to the best of my knowledge  and belief,  I
certify that the information  set forth in this Statement is true,  complete and
correct.


Dated:  May 7, 2004                 /s/ William W. Sherertz
                                    -----------------------
                                    William W. Sherertz

Attention:  Intentional  misstatements  or omissions of fact constitute  Federal
criminal violations. (See 18 U.S.C. 1001.)