Registration No. 33-55117
================================================================================
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                          ----------------------------

                         POST-EFFECTIVE AMENDMENT NO. 1

                                       TO

                                    FORM S-8
                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933
                          ----------------------------

                         BARRETT BUSINESS SERVICES, INC.
             (Exact name of registrant as specified in its charter)

        Maryland                                        52-0812977
(State or other jurisdiction of              (IRS Employer Identification No.)
incorporation or organization)

                            4724 S.W. Macadam Avenue
                             Portland, Oregon 97239
                            Telephone (503) 220-0988
          (Address and telephone number of principal executive offices)

           BARRETT BUSINESS SERVICES, INC., 1993 STOCK INCENTIVE PLAN
                            (Full title of the plan)

                               William W. Sherertz
                                    President
                         Barrett Business Services, Inc.
                            4724 S.W. Macadam Avenue
                             Portland, Oregon 97239
                            Telephone (503) 220-0988
           (Name, address, and telephone number of agent for service)

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

                                   Copies to:
                                 Miller Nash LLP
                              111 S.W. Fifth Avenue
                           Portland, Oregon 97204-3699
                              Attn: Mary Ann Frantz
                                 (503) 224-5858
                          ----------------------------






                                 DEREGISTRATION
                                 --------------

     Pursuant to Registration  Statement on Form S-8 (No.  33-55117) first filed
with the Securities and Exchange Commission on August 17, 1994, Barrett Business
Services,  Inc., a Maryland  corporation,  registered  300,000  shares of common
stock,  $0.01 par value per  share,  for  issuance  under the  Barrett  Business
Services,  Inc.,  1993 Stock  Incentive  Plan. Of the 300,000 shares  originally
registered,  178,243  shares had been  issued and sold as of May 12,  2005.  The
Registration  Statement is hereby amended to deregister 121,757 shares of common
stock,  $0.01 par value per share, of Barrett  Business  Services,  Inc., and to
terminate the registration.





                                   SIGNATURES

     Pursuant to the  requirements of the Securities Act of 1933, the registrant
certifies  that it has  reasonable  grounds to believe  that it meets all of the
requirements  for  filing on Form S-8 and has duly  caused  this  post-effective
amendment  to  registration  statement  to  be  signed  on  its  behalf  by  the
undersigned,  thereunto  duly  authorized,  in the  city of  Portland,  state of
Oregon, on the 12th day of May, 2005.

                                   BARRETT BUSINESS SERVICES, INC.
                                   (Registrant)


                                   By     /s/ Michael D. Mulholland            
                                          -------------------------------------
                                          Michael D. Mulholland
                                          Vice President-Finance and Secretary


     Pursuant  to  the   requirements  of  the  Securities  Act  of  1933,  this
post-effective  amendment  to  registration  statement  has been  signed  by the
following persons in the capacities indicated as of the 12th day of May, 2005.


            Signature                                 Title
            ---------                                 -----

(1) Principal Executive Officer
    and Director:

/s/ William W. Sherertz                    President and Chief Executive Officer
---------------------------------          and Director
William W. Sherertz                                           


(2) Principal Financial Officer:

/s/ Michael D. Mulholland                  Vice President-Finance and Secretary
---------------------------------
Michael D. Mulholland


(3) Principal Accounting Officer:

/s/ James D. Miller
---------------------------------
James D. Miller                            Controller and Assistant Secretary


(4) A majority of the Board of Directors:

/s/ Thomas J. Carley
---------------------------------
Thomas J. Carley                           Director


/s/ James B. Hicks
---------------------------------
James B. Hicks                             Director

                                      II-1


/s/ Jon L. Justesen              
---------------------------------
Jon L. Justesen                            Director


/s/ Anthony Meeker               
---------------------------------
Anthony Meeker                             Director


---------------------------------
Nancy B. Sherertz                          Director




                                      II-2