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, Mallorie Burak, Chief Financial Officer of Rainmaker Systems, Inc. (the “Company”), certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that to my knowledge:

(1) the Quarterly Report of the Company on Form 10-Q for the quarterly period ended March 31, 2013, as filed with the Securities and Exchange Commission (the “Report”) fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended; and

(2) the information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ Mallorie Burak

Mallorie Burak

Chief Financial Officer

(Principal Financial Officer and Principal Accounting Officer)

May 14, 2013