Power of Attorney
This Statement confirms that the undersigned, has
authorized and designated Melanie J. Dressel, Kristy W. House
and Miranda Frost, each with full power to act alone, to execute
and file on the undersigned's behalf all Forms 3, 4, and 5
(including any amendments thereto) that the undersigned may be
required to file with the U.S. Securities and Exchange
Commission as a result of the undersigned's ownership of or
transactions in securities of Columbia Banking System, Inc. The
authority of Melanie J. Dressel, Kristy W. House and Miranda
Frost under this Statement shall continue until the undersigned
is not longer required to file Forms 3, 4, and 5 with regard to
his/her ownership of or transactions in securities of Columbia
Banking System, Inc., unless earlier revoked in writing. The
undersigned acknowledges that none of Columbia Banking System,
Inc., Melanie J. Dressel, Kristy W. House, or Miranda Frost is
assuming any of the undersigned's responsibilities to comply
with Section 16 of the Securities Exchange Act of 1934.
Date: October 22, 2003 Signature: /s/ Dan Regis