CTRX Exhibit 23.1 10-K 12.31.12

We consent to the incorporation by reference in the registration statements on Form S-8 (Nos. 333-182569, 333-182598, 333-174671, 333-164021, 333-159733, 333-145450, 333-145449 and 333-136402) of Catamaran Corporation (the Company) of our reports dated March 1, 2013, with respect to the consolidated balance sheets of the Company as of December 31, 2012 and 2011, and the related consolidated statements of operations, comprehensive income, cash flows and shareholders' equity for each of the years in the three-year period ended December 31, 2012, and the effectiveness of internal control over financial reporting as of December 31, 2012, which reports appear in the December 31, 2012 Annual Report on Form 10-K of Catamaran Corporation.