UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of

The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported):

7/18/06

COLUMBIA BANKING SYSTEM, INC.

(Exact name of registrant as specified in its charter)

Washington	0-20288	91-1422237
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)

1301 A Street Tacoma, WA	98402
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code: (253) 305-1900

(Former name or former address, if changed since last report.)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Items to be Included in this Report

Item 5.02(b) Departure of Principal Officer

On July 18, 2006, Evans Q. Whitney announced his intention to retire effective January 1, 2007 as Columbia Banking System, Inc.’s Executive Vice President of Human Resources. After January 1, 2007 the company intends to utilize Mr. Whitney’s 40 years of industry experience on special leadership and employee development assignments.

The information in this Current Report on Form 8-K shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liability of that section, nor shall it be deemed incorporated by reference in any filing or other document pursuant to the Securities Act of 1933, as amended, except as shall be expressly set forth by specific reference in such filing or document.

Item 9.01 Financial Statements and Exhibits

(a) Financial statements. – not applicable

(b) Pro forma financial information. – not applicable

(c) Shell company transactions – not applicable

(d) Exhibits – not applicable

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	COLUMBIA BANKING SYSTEM, INC.
Date: July 20, 2006	/s/ Melanie J. Dressel
	Melanie J. Dressel President and Chief Executive Officer