Exhibit 32.2

CERTIFICATION PURSUANT TO 18 U.S.C. SECTION 1350, AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

I, Jeffrey Park, the Chief Financial Officer of Catamaran Corporation, certify that (i) the Annual Report on Form 10-K of Catamaran Corporation for the year ended December 31, 2013 (the “Form 10-K”) fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934 and (ii) the information contained in the Form 10-K fairly presents, in all material respects, the financial condition and results of operations of Catamaran Corporation

/s/ Jeffrey Park

Jeffrey Park

Chief Financial Officer

March 3, 2014