Investor Relations

Charles River Laboratories Holdings, Inc.,a leading provider of critical research tools and integrated support services that enable innovative and efficient drug discovery and development, announced today that it has filed a registration statement with the Securities and Exchange Commission for a proposed initial public offering of its common stock.

Donaldson, Lufkin & Jenrette Securities Corporation and Lehman Brothers Inc. will act as lead managing underwriters for the offering and ING Barings LLC, SG Cowen Securities Corporation, U.S. Bancorp Piper Jaffray Inc. and DLJdirect Inc. will act as co-managing underwriters. Net proceeds from the offering are expected to be used to pay down indebtedness. All shares in the offering are expected to be sold by Charles River.

A registration statement relating to these securities has been filed with the Securities and Exchange Commission but has not yet become effective. These securities may not be sold nor may offers to buy be accepted prior to the time the registration statement becomes effective. This press release does not constitute an offer to sell or the solicitation of an offer to buy nor shall there be any sale of these securities in any State in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such State.

When available, a copy of the preliminary prospectus may be obtained from the offices of Donaldson, Lufkin & Jenrette Securities Corporation, 277 Park Avenue, New York, NY 10172, 212-892-3000, or by contacting any of the other managing underwriters.