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 Riverbed Technology, Inc. (the “Company”) on Form 10-K for the year ended December 31, 2006 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), Jerry M. Kennelly, as President and Chief Executive Officer of the Company, and Randy S. Gottfried, as Chief Financial Officer of the Company, each hereby certifies, 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: February 8, 2007	/S/    JERRY M. KENNELLY
	Jerry M. Kennelly
	President and Chief Executive Officer (Principal Executive Officer)
Date: February 8, 2007	/S/    RANDY S. GOTTFRIED
	Randy S. Gottfried
	Chief Financial Officer (Principal Financial and Accounting Officer)

A signed original of this written statement required by Section 906 of the Sarbanes-Oxley Act of 2002 has been provided to the Company and will be retained by the Company and furnished to the Securities and Exchange Commission or its staff upon request.