Charles River has previously repurchased approximately 11 million shares under its prior $600 million stock repurchase authorization, and as of July 15, 2010, had approximately 66.3 million shares of common stock outstanding. That authorization, under which there was a remaining balance of approximately $145 million, has been canceled.

Repurchases may be commenced or suspended at any time or from time to time without prior notice, depending on our view of market conditions and other factors. There are currently no specific plans for the shares that may be purchased under the program.

Earnings Release/Webcast Rescheduled

Charles River has rescheduled its second-quarter 2010 earnings release to Monday, August 2, at 6:30 a.m. ET, with a live webcast to discuss matters relating to the press release beginning at 8:30 a.m. ET on the same day. To participate in the webcast, please go to ir.criver.com and select the webcast link. You can also find the associated slide presentation and reconciliations of non-GAAP financial measures to comparable GAAP financial measures on the website.

About Charles River

Accelerating Drug Development. Exactly. Charles River provides essential products and services to help pharmaceutical and biotechnology companies, government agencies and leading academic institutions around the globe accelerate their research and drug development efforts. Our approximately 8,000 employees worldwide are focused on providing clients with exactly what they need to improve and expedite the discovery, development through first-in-human evaluation, and safe manufacture of new therapies for the patients who need them. To learn more about our unique portfolio and breadth of services, visit www.criver.com.

Forward-Looking Statements

This news release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as “anticipate,” “believe,” “expect,” “will,” “may,” “estimate,” “plan,” “outlook,” and “project” and other similar expressions that predict or indicate future events or trends or that are not statements of historical matters. These statements also include statements regarding changes in our expectations regarding stock repurchases; the future demand for drug discovery and development products and services (particularly in light of the challenging economic environment), including the outsourcing of these services and present spending trends by our customers; the development and performance of our services and products; market and industry conditions; and Charles River's future performance. Forward-looking statements are based on Charles River's current expectations and beliefs, and involve a number of risks and uncertainties that are difficult to predict and that could cause actual results to differ materially from those stated or implied by the forward-looking statements. Those risks and uncertainties include, but are not limited to: the ability to successfully integrate businesses we acquire; negative trends in research and development spending, negative trends in the level of outsourced services, or other cost reduction actions by our customers; the ability to convert backlog to sales; special interest groups; contaminations; industry trends; new displacement technologies; USDA and FDA regulations; changes in law; continued availability of products and supplies; loss of key personnel; interest rate and foreign currency exchange rate fluctuations; changes in tax regulation and laws; changes in generally accepted accounting principles; and any changes in business, political, or economic conditions due to the threat of future terrorist activity in the U.S. and other parts of the world, and related U.S. military action overseas. A further description of these risks, uncertainties, and other matters can be found in the Risk Factors detailed in Charles River's Annual Report on Form 10-K as filed on February 19, 2010, as well as other filings we make with the Securities and Exchange Commission. Because forward-looking statements involve risks and uncertainties, actual results and events may differ materially from results and events currently expected by Charles River, and Charles River assumes no obligation and expressly disclaims any duty to update information contained in this news release except as required by law.