SecProbe.io

January 11, 2013

Via E -mail
Clint E. Stein
Chief Financial Officer
Columbia Banking System, Inc.
1301 “A” Street
Tacoma, Washington 98402 -4200

Re: Columbia Banking System, Inc.
Amendment No. 1 to Registration Statement on Form S -4
Filed December 28 , 2012
  File No. 333-184742

Dear Mr. Stein :

We have reviewed the above referenced filing  and have the following comments.  In
some of our comments, we may ask you to provide us with information so we may better
understand your disclosure.

Please respond to this letter by amending your registration statement and providing the
requested inform ation.   If you do not believe our comments apply to your facts and
circumstances or do not believe an amendment is appropriate, please tell us why in your
response.

After reviewing any amendment to your registration statement and the information you
provide in response to these comments, we may have additional comments.

General
1. Regulation S -K requires that certain information be current as of the last completed fiscal
year.  Where appropriate, please update your disclosure to include the information
required by Item 18(a)(7) of Form S -4 for the year ended December 31, 2012.
The Merger
Background of the Merger, page 52
2. We note your response to comment 18 of our letter dated November 29, 2012.  Please
provide the specific details of Columbia’s origina l indication of interest, and the
subsequent enhanced proposal which constituted an approximate 2.3% increase over the
May proposal.

Clint E. Stein
Columbia Banking System, Inc.
January 11, 2013
Page 2

 Sandler O’Neill’s Relationship, page 76

3. We note your response to comment 22  of our letter dated November 29, 2012.  In the  first
paragraph of this section, you state that “Sandler O’Neill has not received any other fees”
from either company; however, in the second paragraph, you disclose many services you
perform for each company and do not disclose the compensation associated with such
servi ces.  Please revise your disclosure to include such fees in accordance with Section
1015 (b)(4) of Regulation M -A.
Litigation Related to the Merger, page 106
4. We note your disclosure that West Coast has agreed to make certain supplemental
disclosures relate d to the proposed merger.  Please identify such disclosures.
Exhibits
5. Please file any remaining exhibits in your next amendment to the registration statement.
We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the fi ling to be certain that the filing s include the information the Securities Act of 1933 and
the Securities Exchange Act of 1934, and all Securities Act and Exchange Act rules, in each case
as applicable, require.   Since the company and its management are in  possession of all facts
relating to a company’s disclosure, they are responsible for the accuracy and adequacy of the
disclosures they have made.

Notwithstanding our comments, in the event you request acceleration of the effective date
of the pending registration statement please provide a written statement from the company
acknowledging that:

 should the Commission or the staff, acting pursuant to delegated authority, declare the
filing effective, it does not foreclose the Commission from taking any a ction with respect
to the filing;

 the action of the Commission or the staff, acting pursuant to delegated authority, in
declaring the filing effective, does not relieve the company from its full responsibility for
the adequacy and accuracy of the disclos ure in the filing; and

 the company may not assert staff comments and the declaration of effectiveness as a
defense in any proceeding initiated by the Commission or any person under the federal
securities laws of the United States.

Please refer to Rules  460 and 461 regarding requests for acceleration.  We will consider a
written request for acceleration of the effective date of the registration statement as confirmation
of the fact that those requesting acceleration are aware of their respective responsi bilities under
the Securities Act of 1933 and the Securities Exchange Act of 1934 as they relate to the proposed

Clint E. Stein
Columbia Banking System, Inc.
January 11, 2013
Page 3

 public offering of the securities specified in the above registration statement.  Please allow
adequate time for us to review any amendment pri or to the requested effective date of the
registration statement.

Please contact Erin Purnell  at (202) 551 -3454  or me at (202) 551 -3464 with any
questions.

Sincerely,

 /s/ Kathryn McHale

Kathryn McHale
Senior Staff Attorney

cc. Via E -mail
 Stephen Klein
 Graham & Dunn  PC