TACOMA, Wash., July 24 /PRNewswire-FirstCall/ -- The Board of Directors of Columbia Banking System, Inc. (Nasdaq: COLB) announced that a quarterly cash dividend of $0.17 per share will be paid on August 20, 2008 to shareholders of record as of the close of business on August 6, 2008.

Melanie Dressel, President and Chief Executive Officer noted, 'Reflecting our well-capitalized position at June 30, 2008, our quarterly cash dividend is being paid at the same level as in the previous five quarters. We value the ongoing investment of our shareholders.'

About Columbia

Headquartered in Tacoma, Washington, Columbia Banking System, Inc. is the holding company of Columbia Bank, a Washington state-chartered full-service commercial bank. With the 2007 acquisitions of Mountain Bank Holding Company and Town Center Bancorp and the 2008 internal merger of its subsidiary, Bank of Astoria, into Columbia Bank, Columbia Banking System has 53 banking offices in Pierce, King, Cowlitz, Kitsap, Thurston and Whatcom counties in Washington State, and Clackamas, Clatsop, Tillamook and Multnomah counties in Oregon. Included in Columbia Bank are former branches of Mt. Rainier National Bank, doing business as Mt. Rainier Bank, with 5 branches in King and Pierce counties. Columbia Bank does business under the Bank of Astoria name at the Bank of Astoria's former branches located in Astoria, Warrenton, Seaside and Cannon Beach in Clatsop County and in Manzanita in Tillamook County. More information about Columbia can be found on its website at http://www.columbiabank.com.

Note Regarding Forward Looking Statements

This news release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, which can be identified by words such as 'may,' 'expected,' 'anticipate', 'continue,' or other comparable words. In addition, all statements other than statements of historical facts that address activities that Columbia expects or anticipates will or may occur in the future are forward-looking statements. Readers are encouraged to read the SEC reports of Columbia, particularly its form 10-K for the Fiscal Year ended December 31, 2006, for meaningful cautionary language discussing why actual results may vary materially from those anticipated by management.

     Contacts: Melanie J. Dressel, President and
               Chief Executive Officer
               (253) 305-1911
               Gary R. Schminkey, Executive Vice President
               and Chief Financial Officer
               (253) 305-1966

SOURCE Columbia Banking System, Inc.