SecProbe.io

August 31, 2011
Via E-Mail

Melanie J. Dressel Chief Executive Officer Columbia Banking System, Inc. 1301 A Street  Tacoma, WA 98402
Re: Columbia Banking System, Inc.
 Form 10-K for the Fiscal Year Ended December 31, 2010
Filed March 1, 2011 Definitive Proxy Statement on Schedule 14A Filed March 21, 2011 Form 10-Q for the Fiscal Quarter Ended June 30, 2011
Filed August 8, 2011 File No. 000-20288

Dear Ms. Dressel:
We have reviewed your 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 within ten business days by amending your filing, by
providing the requested information, or by advi sing us when you will provide the requested
response.  Where we have requested changes in  future filings, please include a draft of your
proposed disclosures that clearly identifies new or revised disclosu res.  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 filing and the information you provide in
response to these comments, including the draf t of your proposed disclosures, we may have
additional comments.    General

 1. Please tell us why you did not check the box on the first page of your 10-K to indicate
whether you have submitted electronically a nd posted on your corporate website every
Interactive Data File requi red to be submitted and posted pursuant to Rule 405 of
Regulation S-T during the preceding 12 months.

Melanie J. Dressel
Columbia Banking System, Inc. August 31, 2011 Page 2

 Item 7. Management’s Discussion and Analysis of  Financial Condition and Results of Operation

 General

 2. In future filings, please include the separate ly-captioned section addressing off-balance
sheet arrangements in the Management’s Disc ussion and Analysis sec tion of your report.
Please refer to Item 303(a)(4)(i) of Regulation S-K.
 Item 8.  Financial Statements and Supplementary Data

 Notes to Consolidated Financial Statements

 Note 1.  Summary of Significant Accounting Policies

 Originated Loans, page 66

 3. In regard to your restructured loans, please tell  us and revise your future filings to address
the following:

 Provide a robust discussion of your restruct ured loan activities. Your discussion
should include in tabular format quantifica tion of the types of concessions made (e.g.
rate reductions, payment extensions, forgiv eness of principal, forbearance or other
actions) and discussion of your successes or failures with the different types of
concessions at 12/31/10, 3/31/11 and 6/30/11; and
 Disclose your policy regarding how many payments the borrower needs to make on
restructured loans before retu rning loans to accrual status.
 Item 11. Executive Compensation (incorporated by reference to the Definitive Proxy Statement
filed March 21, 2011)
 Compensation Discussion and Analysis

 Key Elements

 Short-Term Incentives, page 28

 4. In future filings, please expand your discussi on to provide additional analysis of the
effect of individual performance on incen tive compensation.  We note that your
disclosure suggests that it is a significant factor considered  by the company.  You should
provide additional detail and an analysis of  how individual performance contributed to
actual compensation for the named executive officers.  For example, disclose the elements of individual performance, both quantitative and qualitative, and specific
contributions the company considered in its evaluation.  See Item 402(b)(2)(vii) of
Regulation S-K.

Melanie J. Dressel
Columbia Banking System, Inc. August 31, 2011 Page 3

 Compensation Tables

 Summary Compensation Table, page 35

 5. In the preceding pages, you describe what a ppears to be a non-equity compensation plan
but you have recorded awards under this pl an in the bonus column of the Summary
Compensation Table.  In future filings, please add a non-equity compensation plan column or explain to the staff why this is not appropriate.
 6. Please amend your 10-K to reflect the correct compensation for your executive officers.
We note that Mr. Nelson’s compensation fi gures for 2009 and 2010 do not appear to add
up to the total reflected in your table.
 2010 Grants of Plan-Based Awards, page 36

 7. We note your disclosure in this  section; however, th e triggering event for the GPBA table
is the date on which the compensation comm ittee approved the plan-based award, not the
date on which cash or stock was actually pai d.  In addition, you a ppear to have paid
awards in connection with a non-equity incentiv e plan which would re quire disclosure in
this table of the threshold, target and ma ximum amounts payable.  If you believe that
disclosure of the performance targets is  not required because  it would result in
competitive harm such that the targets coul d be excluded under Instruction 4 to Item
402(b) of Regulation S-K, please provide  supplemental analysis supporting your
conclusion.  In particular, your competitive harm analysis should  justify why you do not
intend to disclose what appear  to be historical financia l performance objectives, and it
should clearly explain the nexus between di sclosure of the historical performance
objectives and the competitive harm that is likely to result from disclosure.
 Item 13. Certain Relationships and Related Transactions, and Di rector Independence
(incorporated by reference to the Definitive Proxy Statement filed March 21, 2011)
 Interest of Management in Certain Transactions, page 49

 8. Please revise the title of this section to aler t the reader to the fact  that the disclosures
required by Item 404 cover transactions for more than just “management” (security
holders covered by Item 403(a) of Regulation S-K are also covered).
 9. Please represent to the staff that your transa ctions with related parties “were made on
substantially the same terms, including interest  rates and collateral, as those prevailing at
the time for comparable loans with  persons not related to the lender
” or provide the
additional disclosures required by Item 404 of  Regulation S-K.  Please make sure all
future filings clarify this disclosure.  Pl ease refer to Instruction 4 to Item 404(a).

Melanie J. Dressel
Columbia Banking System, Inc. August 31, 2011 Page 4

 Item 15. Exhibits, Financial Statement Schedules

 (a)(3) Exhibits, page 110

 10. We are unable to locate the interactive data required to be filed as an exhibit to your
Form 10-K for the fiscal year ended Decem ber 31, 2010 and Forms 10-Q for the fiscal
quarters ended June 30, 2010 and September 30, 2010.  Please advise.  Refer to Item
601(b)(101)(i)(B) of Regulation S-K and Rule 405(f)(2) of Regulation S-T.  Please also
note that the failure to comply with the in teractive data requirements may impair the
company’s eligibility use Form S-3, among other things.
11. Companies are required to post XBRL data on their public websites  by the end of the
calendar day on which a periodic report was f iled with the SEC or was required to be
filed (whichever is earlier), and the XBRL data must remain on the company’s website
for 12 months.  We are unable to lo cate the XBRL data on your website,
https://www.columbiabank.com
.  Please advise.

Signatures, page 111
 12. Your 10-K must be signed by, among others, your controller or principal accounting
officer.  Refer to General Instruction D( 2)(a) of Form 10-K.  We note that Mr.
Schminkey is your chief financial officer, bu t it is unclear whether he is also your
controller or principal accounting officer.  If s o, please confirm.  Further, please ensure
that future filings identify the controller or principal accounting officer as such on the
signature page.
 Form 10-Q for the Period Ended June 30, 2011

 Item 1.  Financial Statements (unaudited)

 Notes to Unaudited Consolidated Condensed Financial Statements

 Note 7.  Allowance for Loan and Lease Losse s and Unfunded Commitments and Letters of
Credit, page 14
 13. We note that you eliminated the unallocated po rtion of the allowance for loan and lease
losses for noncovered loans thr ough a reduction of ($3.3 million)  in the provision for loan
losses during the 3 months ended March 31, 2011 .  We note further th at you recorded a
$854 thousand provision for loan losses for the unallocated portion of the allowance for
loan and lease losses during the 3 months e nded June 30, 2011.  Please tell us and revise
future filings to more clearly describe how you arrived at the allowance for loan losses
amounts allocated to the various loan categor ies versus the unallocated amount. Discuss
any specific trends or changes from prior period s in environment factors that gave rise to
the changes.

Melanie J. Dressel
Columbia Banking System, Inc. August 31, 2011 Page 5

 Note 8.  Covered Assets and FD IC Loss-Sharing Asset, page 19

14. We note that you combined cash receipts, di sposals and changes in cash flows in the
accretable yield rollforward table on page 20.  Please provide us, and revise in future
filings, the rollforward of activity for the accre table yield recorded for purchased loans to
reflect the specific amounts attributable to additions, accretion, disposals of loans, and
reclassifications to or from nonaccretable  difference during the period as required by
ASC Subtopic 310-30-50-2.2.

15. Please provide us with and revise future f ilings, to include a rollfoward of your loans
accounted for under ASC 310-30 which reconciles  your contractual re ceivable to your
carrying amount.  Your revised disclosure s hould also include disaggregated information
pertaining to your nonaccretable yield.

16. Please tell us and disclose how the remain ing amounts of the both the contractual and
expected cash flows are determined at each reporting period.
17. Please tell us and disclose how the amount of movement between the nonaccretable and
accretable differences’ and the related impact on the indemnification asset is determined
at each reporting period. You should discuss the reasons for any material changes in
MD&A and the notes to the financial statemen ts.  In your response,  please also address
the significant increase in the accretable yiel d due to the transfer from the nonaccretable
difference which occurred during fiscal 2010.
 We urge all persons who are responsible for the accuracy and adequacy of the disclosure
in the filing to be certain that the filing include s the information the Securities Exchange Act of
1934 and all applicable Exchange Act rules requir e.  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.
 In responding to our comments, please provi de a written statement from the company
acknowledging that:

 the company is responsible for the adequacy an d accuracy of the disclo sure in the filing;

 staff comments or changes to disclosure in response to staff comments do not foreclose
the Commission from taking any action with respect to the filing; and

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

Melanie J. Dressel
Columbia Banking System, Inc. August 31, 2011 Page 6

 You may contact David Irving, Staff Account ant, at (202) 551-3321, if you have any
questions regarding comments on the financial st atements and related matters.  If you have
additional questions regardi ng financial matters, you may c ontact Marc Thomas, Staff
Accountant, at (202) 551-3452.  Please address questions rega rding all other comments to
Michael F. Johnson, Staff Attorney, at (202) 551-3477 or, if you thereafter need further
assistance, to me at (202) 551-3464.
Sincerely,
   /s/ Kathryn McHale
Kathryn McHale Staff Attorney