Columbia Banking System Announces Date of 4th Quarter and Year 2007 Earnings Release and Conference Call

    TACOMA, Wash., Jan. 7 /PRNewswire-FirstCall/ -- Columbia Banking System
 (Nasdaq:   COLB) today announced that it plans to release its fourth quarter
 and full year 2007 earnings results on Thursday, January 24, 2008. The
 Company will also discuss the quarterly and full-year results on a
 conference call at 1:00 p.m. PST on the same day. Forward-looking and other
 material information may be discussed on this conference call.
 
     Interested investors, analysts, media representatives and the public
 are invited to listen to this discussion by calling 1-888-318-7969;
 Conference ID code 30252038. A conference call replay will be available
 from approximately 3:00 p.m. PST on January 24 through midnight PST on
 Thursday, January 31, 2008. The conference call replay can be accessed by
 dialing 1-800-642-1687 and entering Conference ID code 30252038.
 
     About Columbia
 
     Headquartered in Tacoma, Washington, Columbia Banking System, Inc. is a
 Tacoma-based bank holding company whose wholly owned banking subsidiaries
 are Columbia Bank and Bank of Astoria, which operate a combined total of 53
 branches. Columbia Bank is a Washington state-chartered full-service
 commercial bank. With the July 23, 2007 completion of the acquisitions of
 Mountain Bank Holding Company and Town Center Bancorp, Columbia Bank has 48
 banking offices in Pierce, King, Cowlitz, Kitsap and Thurston counties in
 Washington State, and Clackamas and Multnomah counties in Oregon. Included
 in Columbia Bank are former branches of Mt. Rainier National Bank, doing
 business as Mt. Rainier Bank, with 7 branches in King and Pierce counties.
 Bank of Astoria, a federally insured commercial bank headquartered in
 Astoria, Oregon, operates four branches in Clatsop County: Astoria,
 Warrenton, Seaside and Cannon Beach; and one branch in Manzanita in
 Tillamook County. More information about Columbia can be found on its
 website at http://www.columbiabank.com.
 
     Contact: Jo Anne Coy, Vice President,
 
 

                   Corporate Communications, Investor & Community Relations
                   (253) 305-1965
 
 
 

SOURCE Columbia Banking System