Intralinks (IL) 10-K 2011 FY Annual report

Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report of IntraLinks Holdings, Inc. (the “Company”) on Form 10-K for the period ended December 31, 2011, as filed with the Securities and Exchange Commission on the date hereof (the “Report”), I, Ronald W. Hovsepian, President andChief Executive Officer of the Company, certify, pursuant to 18 U.S.C. Section 1350, as adopted pursuant to Section 906 of the Sarbanes-Oxley Act of 2002, that:

(1) The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

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

Date: March 20, 2012

/s/ Ronald W. Hovsepian

Ronald W. Hovsepian

President and Chief Executive Officer

(Principal Executive Officer)