As filed with the Securities and Exchange Commission on October 8, 2002
                                                Registration No. 333-_______
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


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


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


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



                          COLUMBIA BANKING SYSTEM, INC.
               ---------------------------------------------------
               (Exact name of Company as specified in its charter)



          WASHINGTON                                            91-1422237
-------------------------------                              ----------------
(State or other jurisdiction of                              (I.R.S. Employer
incorporation or organization)                            Identification Number)


                     1301 A STREET, TACOMA, WASHINGTON 98402
          ------------------------------------------------------------
          (Address of principal executive offices, including zip code)


                   2000 AMENDED AND RESTATED STOCK OPTION PLAN
                   -------------------------------------------
                            (Full Title of the Plan)


                             WILLIAM T. WEYERHAUSER
                      CHAIRMAN AND CHIEF EXECUTIVE OFFICER
                          COLUMBIA BANKING SYSTEM, INC.
                                  1301 A STREET
                            TACOMA, WASHINGTON 98402
                                 (253) 305-1900
            --------------------------------------------------------
            (Name, address, including zip code and telephone number,
                   including area code, of agent for service)


                          Copies of communications to:
                        SANDRA L. GALLAGHER-ALFORD, ESQ.
                           DAVIS WRIGHT TREMAINE, LLP
                         1501 FOURTH AVENUE, SUITE 2600
                         SEATTLE, WASHINGTON 98101-1688
                                 (206) 628-7620


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


                         CALCULATION OF REGISTRATION FEE
<TABLE><CAPTION>
==========================     ============     ================     ==================     ============
                               Amount to be     Proposed Maximum     Proposed Maximum       Amount of
Title of Securities to be      Registered       Offering Price       Aggregate Offering     Registration
Registered                     (1) (2)          Per Share(3)         Price (3)              Fee (1) (3)
--------------------------     ------------     ----------------     ------------------     ------------
<S>                            <C>              <C>                  <C>                    <C>
Common Stock issuable upon
exercise of options            740,300          $12.15               $8,721,407.68          $802.37
==========================     ============     ================     ==================     ============
</TABLE>



(1)  Pursuant Form S-8, General Instruction E, of the Securities Act of 1933,
     this Registration Statement registers 740,300 additional shares of common
     stock issuable under the Company's 2000 Amended and Restated Stock Option
     Plan, which, as amended effective April 25, 2000 (the "Plan"), provides for
     the issuance of up to 1,095,734 shares of common stock. The Company
     previously registered, on Registration Statement No. 333-40316, the 454,781
     shares of common stock issuable under the Company's 2000 Amended and
     Restated Stock Option Plan, as amended in 1997. The Company paid the
     Securities and Exchange Commission a fee of $2,010.72 in connection with
     that registration statement. The amount to be registered accounts for the
     following dividends: On May 15, 2001, the Company announced a 10% stock
     dividend payable on June 15, 2001, to shareholders of record as of May 29,
     2001. On April 2, 2002, the Company announced a 5% stock dividend payable
     on April 30, 2002, to shareholders of record as of April 16, 2002.

(2)  This Registration Statement also includes an indeterminable number of
     additional shares that may become issuable (a) as a result of terminated,
     expired or surrendered options to purchase the Company's common stock
     issued under the Plan, and (b) pursuant to Rule 416(a), any increases in
     the number of shares offered under the Plan to prevent dilution resulting
     from stock splits, stock dividends or similar transactions.

(3)  Estimated solely for the purpose of calculating the registration fee
     pursuant to Rule 457(h) under the Securities Act of 1933, based on (a) the
     exercise prices of options to acquire 441,055 shares of the Company's
     common stock which have been granted under the 2000 Amended and Restated
     Stock Option Plan and which range from $9.10 to $14.07 per share, and (b)
     the average of the high and low prices of the common stock quoted on
     October 4, 2002, by the Nasdaq National Market System with respect to
     299,245 shares of common stock as to which options have not been granted as
     of the date of filing this Registration Statement.
<PAGE>
                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

         Columbia Banking System, Inc. (the "COMPANY") will send or give the
documents containing the information required by Part I of this registration
statement on Form S-8 (the "REGISTRATION STATEMENT") to each participant in the
Company's Amended and Restated Stock Option Plan, as amended effective April 25,
2000 (the "PLAN"), as specified by Rule 428(b)(1) under the Securities Act of
1933 (the "SECURITIES ACT"). Such documents, and the documents incorporated by
reference into this Registration Statement pursuant to Item 3 of Part II, taken
together, constitute a prospectus that meets the requirements of Section 10(a)
of the Securities Act.

ITEM 1.  PLAN INFORMATION.*

ITEM 2.  REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.*

--------------
*  Information required by Part I of Form S-8 is omitted from this Registration
Statement in accordance with Rule 428 under the Securities Act, and the Note to
Part I of Form S-8.


                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents are hereby incorporated by reference into this
Registration Statement:

1.       The Company's Annual Report on Form 10-K for the fiscal year ended
         DECEMBER 31, 2001.

2.       All reports filed pursuant to Section 13(a) or 15(d) of the Securities
         Exchange Act of 1934 (the "EXCHANGE Act") since the end of the fiscal
         year covered by the Company's Form 10-K referred to in (1) above.

3.       The Company's registration statement on Form S-2 (No. 333-14465) filed
         with the SEC on October 18, 1996, and Amendment No. 1 and Amendment No.
         2 to the Form S-2 filed with the SEC on October 28, 1996 and November
         6, 1996, respectively, as to the description of the Company's
         securities.

4.       All documents subsequently filed by the Company pursuant to Sections
         13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of
         a post-effective amendment which indicates that all securities offered
         have been sold or which deregisters all securities then remaining
         unsold, shall be deemed to be incorporated herein by reference and to
         be a part hereof from the date of the filing of such documents with the
         Commission.

ITEM 4.  DESCRIPTION OF SECURITIES.

         Not applicable.

ITEM 5.  INTEREST OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         The Washington Business Corporation Act, RCW Chapter 23B.08, authorizes
indemnification of directors, officers and employees under certain
circumstances. The Company's Amended and Restated Articles of Incorporation
provide, among other things, for the indemnification of directors, and authorize
the Board to pay reasonable expenses incurred by, or to satisfy a judgment
penalty, settlement or fine against, a current or former director in connection
with any personal legal liability incurred by the individual while acting for
the Company within the scope of employment, and which was not the result of
conduct finally adjudged to be "egregious conduct." "Egregious conduct" is
defined as acts of omissions that involve intentional misconduct, a knowing

                                        1
<PAGE>
violation of law, or participation in any transaction from which the person will
personally receive a benefit in money, property or services to which that person
is not legally entitled. The Amended and Restated Articles of Incorporation also
include a provision that limits the liability of directors of the Company from
any personal liability to the Company or its shareholders for monetary damages
not found to have been egregious. The Company has purchased an officers and
directors liability insurance policy which provides for insurance of directors
and officers of the Company against certain liabilities they may incur in their
capacities as such.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable.

ITEM 8.  EXHIBITS.

         The following Exhibits are filed as a part of this Registration
Statement:

EXHIBIT
NUMBER   DESCRIPTION
-------  -----------
4.1      Amended and Restated Articles of Incorporation (3)
4.2      Restated Bylaws (1)
4.3      2000 Amended and Restated Stock Option Plan (2)
5.1      Opinion of Davis Wright Tremaine LLP (4)
23.1     Consent of Davis Wright Tremaine LLP (contained in opinion filed
         as Exhibit 5.1)
23.2     Consent of Deloitte & Touche LLP (4)
24       Power of Attorney (4)
-------------
(1) Incorporated by reference to the Company's Annual Report on Form 10-K for
    the year ended December 31, 1999.
(2) Incorporated by reference to the Company's Form 10-Q for the quarter ended
    June 30, 2000.
(3) Incorporated by reference to the Company's Quarterly Report on Form 10-Q for
    the quarter ended June 30, 2001.
(4) Filed with this Registration Statement.

ITEM 9.  UNDERTAKINGS.

         (a)  The Company hereby undertakes to do the following:

              (1) File, during any period in which it offers or sells
                  securities, a post-effective amendment to this Registration
                  Statement to:

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

                  (ii)  Reflect in the prospectus facts or events which,
                        individually or together, represent a fundamental change
                        in the information in this Registration Statement; and

                  (iii) Include any additional or changed material information
                        on the plan of distribution.

              (2) For determining liability under the Securities Act, treat each
                  post-effective amendment as a new registration statement of
                  the securities offered, and the offering of the securities at
                  that time to be the initial bona fide offering.

              (3) File a post-effective amendment to remove from registration
                  any of the securities that remain unsold at the end of the
                  offering.

         (b)  Insofar as indemnification for liabilities arising under the
              Securities Act may be permitted to directors, officers and
              controlling persons of the Company pursuant to the foregoing
              provisions, or otherwise, the Company has been advised that in the
              opinion of the SEC such indemnification is against public policy
              as expressed in the Securities Act and is, therefore,
              unenforceable. In the event that a claim for indemnification
              against such liabilities (other than the payment by the Company of
              expenses incurred or paid by a director, officer or controlling
              person of the Company in the successful defense of any action,

                                        2
<PAGE>

              suit or proceeding) is asserted by such director, officer or
              controlling person in connection with the securities being
              registered, the Company 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 it is against public policy as expressed in the
              Securities Act and will be governed by the final adjudication of
              such issue.

         (c)  (1) For determining any liability under the Securities Act, treat
                  the information omitted from the form of prospectus filed as
                  part of this Registration Statement in reliance upon Rule 430A
                  and contained in a form of prospectus filed by the Company
                  pursuant to Rule 424(b)(1) or (4), or 497(h) under the
                  Securities Act as part of this Registration Statement as of
                  the time the Commission declared it effective.

              (2) For determining any liability under the Securities Act, treat
                  each post-effective amendment that contains a form of
                  prospectus as a new registration statement for the securities
                  offered in the registration statement, and offering of the
                  securities at that time as the initial bona fide offering of
                  those securities.









                                        3
<PAGE>
                                   SIGNATURES

         Pursuant to the requirements of the Securities Act, the Company
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 Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Tacoma, State of Washington, October 7, 2002.


                                              COLUMBIA BANKING SYSTEM, INC.

                                              By:  /s/ William T. Weyerhaeuser
                                                   ---------------------------
                                                   William T. Weyerhaeuser
                                                   Chief Executive Officer




         Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed by the following persons in the capacities indicated,
on September 25, 2002.

William T. Weyerhaeuser         Chairman and Chief Executive Officer
Melanie J. Dressel              Director, President and Chief Operating Officer
Richard S. DeVine               Director
Jack Fabulich                   Director
John P. Folsom                  Director
John A. Halleran                Director
Thomas M. Hulbert               Director
Thomas L. Matson                Director
Donald Rodman                   Director
James M. Will                   Director

William T. Weyerhaeuser, by signing his name below, signs this Registration
Statement pursuant to powers of attorney duly executed by the persons named
above, filed with the SEC as an exhibit to this Registration Statement, on
behalf of such persons, all in the capacities and on the date stated. Such
persons represent all of the Company's directors.


/s/ William T. Weyerhaeuser
---------------------------------
William T. Weyerhaeuser, Chairman
Attorney-in-fact







                                        4
<PAGE>


EXHIBIT
NUMBER           DESCRIPTION
-------          -----------
4.1              Amended and Restated Articles of Incorporation (3)
4.2              Restated Bylaws (1)
4.3              2000 Amended and Restated Stock Option Plan (2)
5.1              Opinion of Davis Wright Tremaine LLP (4)
23.1             Consent of Davis Wright Tremaine LLP (contained in opinion
                 filed as Exhibit 5.1)
23.2             Consent of Deloitte & Touche LLP (4)
24               Power of Attorney (4)

-------------
(1)  Incorporated by reference to the Company's Annual Report on Form 10-K for
     the year ended December 31, 1999.
(2)  Incorporated by reference to the Company's Form 10-Q for the quarter ended
     June 30, 2000.
(3)  Incorporated by reference to the Company's Quarterly Report on Form 10-Q
     for the quarter ended June 30, 2001.
(4)  Filed with this Registration Statement.













                                        5
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{"company-data": {"conformed-name": "COLUMBIA BANKING SYSTEM INC", "cik": "0000887343", "assigned-sic": "6022", "irs-number": "911422237", "state-of-incorporation": "WA", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-100420", "film-number": "02784218"}, "business-address": {"street1": "1102 BROADWAY PLAZA", "city": "TACOMA", "state": "WA", "zip": "98402", "phone": "2533051900"}, "mail-address": {"street1": "1102 BROADWAY PLAZA", "city": "TACOMA", "state": "WA", "zip": "98402"}}
As filed with the Securities and Exchange Commission on October 8, 2002
                                                Registration No. 333-_______
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

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

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

                          COLUMBIA BANKING SYSTEM, INC.
               ---------------------------------------------------
               (Exact name of Company as specified in its charter)

          WASHINGTON                                            91-1422237
-------------------------------                              ----------------
(State or other jurisdiction of                              (I.R.S. Employer
incorporation or organization)                            Identification Number)

                     1301 A STREET, TACOMA, WASHINGTON 98402
          ------------------------------------------------------------
          (Address of principal executive offices, including zip code)

                   2000 AMENDED AND RESTATED STOCK OPTION PLAN
                   -------------------------------------------
                            (Full Title of the Plan)

                             WILLIAM T. WEYERHAUSER
                      CHAIRMAN AND CHIEF EXECUTIVE OFFICER
                          COLUMBIA BANKING SYSTEM, INC.
                                  1301 A STREET
                            TACOMA, WASHINGTON 98402
                                 (253) 305-1900
            --------------------------------------------------------
            (Name, address, including zip code and telephone number,
                   including area code, of agent for service)

                          Copies of communications to:
                        SANDRA L. GALLAGHER-ALFORD, ESQ.
                           DAVIS WRIGHT TREMAINE, LLP
                         1501 FOURTH AVENUE, SUITE 2600
                         SEATTLE, WASHINGTON 98101-1688
                                 (206) 628-7620

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

                         CALCULATION OF REGISTRATION FEE
==========================     ============     ================     ==================     ============
                               Amount to be     Proposed Maximum     Proposed Maximum       Amount of
Title of Securities to be      Registered       Offering Price       Aggregate Offering     Registration
Registered                     (1) (2)          Per Share(3)         Price (3)              Fee (1) (3)
--------------------------     ------------     ----------------     ------------------     ------------
Common Stock issuable upon
exercise of options            740,300          $12.15               $8,721,407.68          $802.37
==========================     ============     ================     ==================     ============
(1)  Pursuant Form S-8, General Instruction E, of the Securities Act of 1933,
     this Registration Statement registers 740,300 additional shares of common
     stock issuable under the Company's 2000 Amended and Restated Stock Option
     Plan, which, as amended effective April 25, 2000 (the "Plan"), provides for
     the issuance of up to 1,095,734 shares of common stock. The Company
     previously registered, on Registration Statement No. 333-40316, the 454,781
     shares of common stock issuable under the Company's 2000 Amended and
     Restated Stock Option Plan, as amended in 1997. The Company paid the
     Securities and Exchange Commission a fee of $2,010.72 in connection with
     that registration statement. The amount to be registered accounts for the
     following dividends: On May 15, 2001, the Company announced a 10% stock
     dividend payable on June 15, 2001, to shareholders of record as of May 29,
     2001. On April 2, 2002, the Company announced a 5% stock dividend payable
     on April 30, 2002, to shareholders of record as of April 16, 2002.

(2)  This Registration Statement also includes an indeterminable number of
     additional shares that may become issuable (a) as a result of terminated,
     expired or surrendered options to purchase the Company's common stock
     issued under the Plan, and (b) pursuant to Rule 416(a), any increases in
     the number of shares offered under the Plan to prevent dilution resulting
     from stock splits, stock dividends or similar transactions.

(3)  Estimated solely for the purpose of calculating the registration fee
     pursuant to Rule 457(h) under the Securities Act of 1933, based on (a) the
     exercise prices of options to acquire 441,055 shares of the Company's
     common stock which have been granted under the 2000 Amended and Restated
     Stock Option Plan and which range from $9.10 to $14.07 per share, and (b)
     the average of the high and low prices of the common stock quoted on
     October 4, 2002, by the Nasdaq National Market System with respect to
     299,245 shares of common stock as to which options have not been granted as
     of the date of filing this Registration Statement.
PART I

              INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS

         Columbia Banking System, Inc. (the "COMPANY") will send or give the
documents containing the information required by Part I of this registration
statement on Form S-8 (the "REGISTRATION STATEMENT") to each participant in the
Company's Amended and Restated Stock Option Plan, as amended effective April 25,
2000 (the "PLAN"), as specified by Rule 428(b)(1) under the Securities Act of
1933 (the "SECURITIES ACT"). Such documents, and the documents incorporated by
reference into this Registration Statement pursuant to Item 3 of Part II, taken
together, constitute a prospectus that meets the requirements of Section 10(a)
of the Securities Act.

ITEM 1.  PLAN INFORMATION.*

ITEM 2.  REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.*

--------------
*  Information required by Part I of Form S-8 is omitted from this Registration
Statement in accordance with Rule 428 under the Securities Act, and the Note to
Part I of Form S-8.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents are hereby incorporated by reference into this
Registration Statement:

1.       The Company's Annual Report on Form 10-K for the fiscal year ended
         DECEMBER 31, 2001.

2.       All reports filed pursuant to Section 13(a) or 15(d) of the Securities
         Exchange Act of 1934 (the "EXCHANGE Act") since the end of the fiscal
         year covered by the Company's Form 10-K referred to in (1) above.

3.       The Company's registration statement on Form S-2 (No. 333-14465) filed
         with the SEC on October 18, 1996, and Amendment No. 1 and Amendment No.
         2 to the Form S-2 filed with the SEC on October 28, 1996 and November
         6, 1996, respectively, as to the description of the Company's
         securities.

4.       All documents subsequently filed by the Company pursuant to Sections
         13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to the filing of
         a post-effective amendment which indicates that all securities offered
         have been sold or which deregisters all securities then remaining
         unsold, shall be deemed to be incorporated herein by reference and to
         be a part hereof from the date of the filing of such documents with the
         Commission.

ITEM 4.  DESCRIPTION OF SECURITIES.

         Not applicable.

ITEM 5.  INTEREST OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         The Washington Business Corporation Act, RCW Chapter 23B.08, authorizes
indemnification of directors, officers and employees under certain
circumstances. The Company's Amended and Restated Articles of Incorporation
provide, among other things, for the indemnification of directors, and authorize
the Board to pay reasonable expenses incurred by, or to satisfy a judgment
penalty, settlement or fine against, a current or former director in connection
with any personal legal liability incurred by the individual while acting for
the Company within the scope of employment, and which was not the result of
conduct finally adjudged to be "egregious conduct." "Egregious conduct" is
defined as acts of omissions that involve intentional misconduct, a knowing

                                        1
violation of law, or participation in any transaction from which the person will
personally receive a benefit in money, property or services to which that person
is not legally entitled. The Amended and Restated Articles of Incorporation also
include a provision that limits the liability of directors of the Company from
any personal liability to the Company or its shareholders for monetary damages
not found to have been egregious. The Company has purchased an officers and
directors liability insurance policy which provides for insurance of directors
and officers of the Company against certain liabilities they may incur in their
capacities as such.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable.

ITEM 8.  EXHIBITS.

         The following Exhibits are filed as a part of this Registration
Statement:

EXHIBIT
NUMBER   DESCRIPTION
-------  -----------
4.1      Amended and Restated Articles of Incorporation (3)
4.2      Restated Bylaws (1)
4.3      2000 Amended and Restated Stock Option Plan (2)
5.1      Opinion of Davis Wright Tremaine LLP (4)
23.1     Consent of Davis Wright Tremaine LLP (contained in opinion filed
         as Exhibit 5.1)
23.2     Consent of Deloitte & Touche LLP (4)
24       Power of Attorney (4)
-------------
(1) Incorporated by reference to the Company's Annual Report on Form 10-K for
    the year ended December 31, 1999.
(2) Incorporated by reference to the Company's Form 10-Q for the quarter ended
    June 30, 2000.
(3) Incorporated by reference to the Company's Quarterly Report on Form 10-Q for
    the quarter ended June 30, 2001.
(4) Filed with this Registration Statement.

ITEM 9.  UNDERTAKINGS.

         (a)  The Company hereby undertakes to do the following:

              (1) File, during any period in which it offers or sells
                  securities, a post-effective amendment to this Registration
                  Statement to:

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

                  (ii)  Reflect in the prospectus facts or events which,
                        individually or together, represent a fundamental change
                        in the information in this Registration Statement; and

                  (iii) Include any additional or changed material information
                        on the plan of distribution.

              (2) For determining liability under the Securities Act, treat each
                  post-effective amendment as a new registration statement of
                  the securities offered, and the offering of the securities at
                  that time to be the initial bona fide offering.

              (3) File a post-effective amendment to remove from registration
                  any of the securities that remain unsold at the end of the
                  offering.

         (b)  Insofar as indemnification for liabilities arising under the
              Securities Act may be permitted to directors, officers and
              controlling persons of the Company pursuant to the foregoing
              provisions, or otherwise, the Company has been advised that in the
              opinion of the SEC such indemnification is against public policy
              as expressed in the Securities Act and is, therefore,
              unenforceable. In the event that a claim for indemnification
              against such liabilities (other than the payment by the Company of
              expenses incurred or paid by a director, officer or controlling
              person of the Company in the successful defense of any action,

                                        2
suit or proceeding) is asserted by such director, officer or
              controlling person in connection with the securities being
              registered, the Company 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 it is against public policy as expressed in the
              Securities Act and will be governed by the final adjudication of
              such issue.

         (c)  (1) For determining any liability under the Securities Act, treat
                  the information omitted from the form of prospectus filed as
                  part of this Registration Statement in reliance upon Rule 430A
                  and contained in a form of prospectus filed by the Company
                  pursuant to Rule 424(b)(1) or (4), or 497(h) under the
                  Securities Act as part of this Registration Statement as of
                  the time the Commission declared it effective.

              (2) For determining any liability under the Securities Act, treat
                  each post-effective amendment that contains a form of
                  prospectus as a new registration statement for the securities
                  offered in the registration statement, and offering of the
                  securities at that time as the initial bona fide offering of
                  those securities.

                                        3
SIGNATURES

         Pursuant to the requirements of the Securities Act, the Company
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 Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Tacoma, State of Washington, October 7, 2002.

                                              COLUMBIA BANKING SYSTEM, INC.

                                              By:  /s/ William T. Weyerhaeuser
                                                   ---------------------------
                                                   William T. Weyerhaeuser
                                                   Chief Executive Officer

         Pursuant to the requirements of the Securities Act, this Registration
Statement has been signed by the following persons in the capacities indicated,
on September 25, 2002.

William T. Weyerhaeuser         Chairman and Chief Executive Officer
Melanie J. Dressel              Director, President and Chief Operating Officer
Richard S. DeVine               Director
Jack Fabulich                   Director
John P. Folsom                  Director
John A. Halleran                Director
Thomas M. Hulbert               Director
Thomas L. Matson                Director
Donald Rodman                   Director
James M. Will                   Director

William T. Weyerhaeuser, by signing his name below, signs this Registration
Statement pursuant to powers of attorney duly executed by the persons named
above, filed with the SEC as an exhibit to this Registration Statement, on
behalf of such persons, all in the capacities and on the date stated. Such
persons represent all of the Company's directors.

/s/ William T. Weyerhaeuser
---------------------------------
William T. Weyerhaeuser, Chairman
Attorney-in-fact

                                        4
EXHIBIT
NUMBER           DESCRIPTION
-------          -----------
4.1              Amended and Restated Articles of Incorporation (3)
4.2              Restated Bylaws (1)
4.3              2000 Amended and Restated Stock Option Plan (2)
5.1              Opinion of Davis Wright Tremaine LLP (4)
23.1             Consent of Davis Wright Tremaine LLP (contained in opinion
                 filed as Exhibit 5.1)
23.2             Consent of Deloitte & Touche LLP (4)
24               Power of Attorney (4)

-------------
(1)  Incorporated by reference to the Company's Annual Report on Form 10-K for
     the year ended December 31, 1999.
(2)  Incorporated by reference to the Company's Form 10-Q for the quarter ended
     June 30, 2000.
(3)  Incorporated by reference to the Company's Quarterly Report on Form 10-Q
     for the quarter ended June 30, 2001.
(4)  Filed with this Registration Statement.

                                        5