Investor Relations

 WILMINGTON, Mass.--(BUSINESS WIRE)--Aug. 14, 2003--

            Handheld Endotoxin Detection System Gives Fast,
                    Quantitative Results with Ease

Charles River Laboratories International, Inc. (NYSE: CRL), a leading provider of pre-clinical research products and services to pharmaceutical and biotechnology companies, launched the Endosafe(R)-PTS today.

The PTS is a portable test system based on the Limulus Amebocyte Lysate (LAL) assay. The LAL test is used to detect microbial contaminants in injectable drugs and medical devices.

The PTS utilizes disposable cartridges loaded with FDA-licensed LAL reagents with a handheld spectrophotometer. Testing can be performed at the point of sample collection; quantitative LAL results are available in approximately 15 minutes, about 45 minutes less than the time required for the conventional chromogenic LAL test.

The PTS can be used in quality control laboratories and production areas to troubleshoot problematic products and to get an early indication of endotoxin levels. In addition, the PTS can be used in research laboratories for water and sample testing in R&D applications. Early adopters of the PTS system are investigating applications in dialysis clinics, hospital compounding pharmacies, dental offices, and nuclear pharmacies. The licensed applications for in-process and final product release testing for drugs and devices are pending FDA approval.

"We are very pleased to bring this breakthrough technology to the marketplace," said James C. Foster, Chairman, President and Chief Executive Officer of Charles River Laboratories. "We believe that the PTS test platform will allow us to expand our endotoxin detection market in the future to include air, water, and surface monitoring in the clinical, environmental, and aerospace arenas."

"The PTS system mirrors the conventional LAL assay in method, sensitivity and software compatibility, but has been adapted for one-button operation and fast results," said Foster T. Jordan, Charles River's Executive Director, In Vitro Detection Systems. "Where turnaround time in internal labs and cost of contract testing are issues, the PTS is the ideal solution."

About Charles River Laboratories, Inc.

Charles River Laboratories, based in Wilmington, Massachusetts, is a leading provider of critical research tools and integrated support services that enable innovative and efficient drug discovery and development. The Company is the global leader in providing the animal research models required in research and development for new drugs, devices and therapies. The Company also offers a broad and growing portfolio of biomedical products and services that enable customers to reduce cost, increase speed, and enhance productivity and effectiveness in drug discovery and development. Charles River's customer base spans over 50 countries, and includes all of the major pharmaceutical companies, biotechnology companies, and many leading hospitals and academic institutions. The Company operates 82 facilities in 16 countries worldwide.

Caution Concerning Forward-Looking Statements. This document 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," "estimate," "plan," and "project" and other similar expressions that predict or indicate future events or trends or that are not statements of historical matters. These statements are based on management's current expectations, and involve a number of risks and uncertainties that could cause actual results to differ materially from those stated or implied by the forward-looking statements, and the Company expressly does not undertake any duty to update forward-looking statements, which speak only as of the date of this document. Those risks and uncertainties include, but are not limited to: a decrease in pre-clinical research and development spending or a decrease in the level of outsourced services; acquisition integration risks; special interest groups; contaminations; industry trends; new displacement technologies; outsourcing trends; 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 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 the Company's Annual Report on Form 10-K as filed on March 20, 2003, with the Securities and Exchange Commission.

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    CONTACT: Charles River Laboratories, Inc.
             Media:
             Julie Palm, 978-658-6000
             jpalm@criver.com
             or
             Technical Services:
             Kerri Mulik, 800-762-7016
             kmulik@criver.com
             or
             Investor Relations:
             Susan E. Hardy, 978-658-6000 ext.1616
             shardy@criver.com

    SOURCE: Charles River Laboratories, Inc.