Riverbed Technology (RVBD)

Revenue and Non-GAAP EPS Expected to Exceed Previous Guidance

SAN FRANCISCO – January 20, 2009 – Riverbed Technology (NASDAQ: RVBD) today announced that it expects fourth quarter fiscal 2008 revenues of approximately $91 to $92 million, representing a Riverbed^® record for quarterly revenue, and approximately 20% growth over the same period one year ago. Fourth quarter GAAP EPS is expected to be in the range of $0.29 to $0.33 per diluted share. GAAP EPS estimates benefit from the expected reduction of the valuation allowance on Riverbed’s deferred tax assets. Fourth quarter non-GAAP EPS is expected to be in the range of $0.18 to $0.19 per diluted share. Non-GAAP EPS excludes the impact of stock-based compensation, stock-based payroll expenses and related income tax effects, and the reduction in the valuation allowance related to deferred tax assets.

These preliminary fourth quarter revenue and non-GAAP EPS results exceed the guidance the company provided on October 23, 2008. At that time, the company estimated revenue between $87 and $90 million and non-GAAP earnings between $0.15 and $0.17 per share.

“We are pleased with our preliminary fourth quarter financial results,” said Jerry M. Kennelly, Riverbed president and CEO. “We achieved full year 2008 revenue growth of approximately 40% against the backdrop of a challenging global economy. Our results this quarter and customer feedback reinforce that WAN optimization and the ROI benefits provided by Riverbed Steelhead^® products resonate in any economic environment.”

As of December 31, 2008, cash, cash equivalents and short-term investments totaled approximately $268 million and the company continues to have no debt. During the fourth quarter, Riverbed repurchased 2.5 million shares of Riverbed stock at a cost of approximately $25 million under the company’s stock repurchase plan and issued the $11 million settlement payment to Quantum Corporation that was recognized during the third quarter 2008.

Riverbed will release fourth quarter and fiscal year 2008 financial results after the market close on Tuesday, February 3, 2009. A live webcast of the earnings conference call will be made available at 2:00 p.m. Pacific Time on the Riverbed Investor Relations website at www.riverbed.com/investors. The conference call and webcast will include forward-looking information. A replay of the audio webcast will be available for 12 months.