Charles River Laboratories Receives FDA Approval for Sale and Marketing of First Portable Endotoxin Test System, the Endosafe-PTS(TM); Breakthrough One-Button Technology Revolutionizes Endotoxin Detection

Charles River Laboratories International, Inc.
(NYSE:CRL) has received FDA approval that allows for the sale and
marketing of the first portable endotoxin test system, the
Endosafe-PTS(TM). The patented Endosafe-PTS(TM) is used to detect
endotoxin contaminants in drugs, medical devices, biological products
and other unique applications including NASA spacecraft missions. The
PTS is a revolutionary technology that:

-- is a portable handheld system that can be used for point of
use testing

-- provides quantitative results in 15 minutes rather than
current methods which take from 45 minutes to several days

-- requires minimal technical training - just insert the PTS
cartridge, add sample and read quantitative results

The Endosafe-PTS(TM) system can accelerate the discovery and
development of new drugs by offering quick and easy endotoxin
contamination results, thereby saving pharmaceutical companies,
medical professionals and scientists both time and money in the
manufacturing process.

Real world applications for the PTS system include:

-- Medical devices & injectable drugs

-- Dialysis clinics

-- Nuclear medicine

-- Hospitals

-- Stem cell research

-- Planetary protection

The PTS utilizes disposable cartridges that are pre-loaded with
reagents and a portable, handheld reader to provide quantitative
endotoxin amounts. Because of its portability, the PTS allows for
testing to be performed at the point of sample collection. In
addition, the simple one-button operation requires minimal technical
training and the data can be stored in the PTS, downloaded to a
computer and/or printed.
NASA recently used the Endosafe-PTS(TM) to monitor the environment
for microbial contamination during the construction of the Mars
exploration rovers "Spirit" and "Opportunity". PTS units are scheduled
to be flown to the International Space Station to perform
environmental monitoring for microbial contamination. Future
applications of PTS may include detecting signs of microbial life on
Mars.

About Charles River Laboratories

Charles River Laboratories, based in Wilmington, Massachusetts,
U.S., is a global provider of solutions that advance the drug
discovery and development process. Our leading-edge products and
services are designed to enable our clients to bring drugs to market
faster and more efficiently. Backed by our rigorous, best-in-class
procedures and our proven data collection, analysis and reporting
capabilities, our products and services are organized into three
categories spanning every step of the drug development pipeline:
Research Models and Services, Preclinical Services, and Clinical
Services. Charles River's customer base includes all of the major
pharmaceutical companies and many biotechnology companies, government
agencies and leading hospitals and academic institutions. Charles
River's 8,500 employees serve clients in more than 50 countries. For
more information on Charles River, visit our website at
www.criver.com.

Caution Concerning 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.
Forward-looking statements include the statements in this notice
regarding Charles River's expectation regarding the markets for and
potential applications of the PTS systems. Charles River cannot
guarantee that the markets for PTS will develop as expected, or that
specific applications of the PTS system will be viable.
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. 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
March 14, 2006, as well as other filings we make with the Securities
and Exchange Commission. Charles River assumes no obligation and
expressly disclaims any duty to update information contained in this
release except as required by law.