Exhibit

We consent to the incorporation by reference in Registration Statement Nos. 333-195456, 333-187690, 333-160371, 333-160370, 333-125298 and 333-225955 on Form S-8 and Registration Statement Nos. 333-206125 and 333-226585 on Form S-3 of our reports dated February 27, 2019, relating to the consolidated financial statements of Columbia Banking System Inc., and the effectiveness of Columbia Banking System, Inc.'s internal control over financial reporting, appearing in this Annual Report on Form 10-K of Columbia Banking System, Inc., for the year ended December 31, 2018.