Forrester Research, Inc. (Nasdaq: FORR) today announced that on January 26, 2006, its independent registered public accounting firm, BDO Seidman, LLP, informed the company that it had incorrectly accounted for performance-based stock options to purchase 940,500 shares of common stock granted on March 31, 2005. As a result of the error, Forrester did not record non-cash stock-based compensation expense of approximately $290,000 for the quarter ended June 30, 2005 and approximately $729,000 for the quarter ended September 30, 2005. Forrester expects that its fourth quarter results will include a non-cash stock compensation expense of approximately $537,000 for the fourth quarter relating to these options. After consultation with BDO Seidman and the Audit Committee of the Board of Directors, the company has decided to restate its financial statements for these two periods. Revised reports on Form 10-Q for the affected quarters will be filed as soon as is practicable.

In addition, as a result of the error, Forrester expects to report a material weakness with respect to its internal controls over accounting for stock-based compensation as of December 31, 2005. The company plans to report fourth-quarter and full-year 2005 results on February 1, 2006 before the market opens and will host a conference call at 11:00 a.m. Eastern time.