Exhibit 99.1

     QUEST DIAGNOSTICS INCREASES SHARE REPURCHASE AUTHORITY BY $300 MILLION
                      AND DECLARES QUARTERLY CASH DIVIDEND

TETERBORO, N.J., July 22, 2004--Quest Diagnostics Incorporated (NYSE: DGX), the
nation's leading provider of diagnostic testing, information and services,
announced that its Board of Directors increased the company's share repurchase
authorization by an additional $300 million. In addition, the Board declared a
quarterly cash dividend on Quest Diagnostics common stock of $0.15 per share,
payable on October 22, 2004 to shareholders of record on October 8, 2004.

Through June 30, 2004, the company had repurchased $529 million of common stock
of the $600 million previously authorized. The expansion of the repurchase
program is expected to have no impact on the company's growth strategy or its
ability to finance future growth. The company had approximately 102 million
shares outstanding as of June 30, 2004.

"The expansion of our share repurchase program provides another means to return
value to our shareholders," said Surya N. Mohapatra, Ph.D., President and Chief
Executive Officer. "The Board's actions reflect a high level of confidence in
the company's financial strength and our ability to continue generating strong
cash flows."

Quest Diagnostics will hold its second quarter conference call on July 22 at
8:30 A.M. Eastern Time. To hear a simulcast of the call over the Internet or a
replay, registered analysts may access StreetEvents at: www.streetevents.com,
and all others may access the Quest Diagnostics website at:
www.questdiagnostics.com. In addition, a replay of the call will be available
from 10 A.M. on July 22 through 11 P.M. on August 20 to investors in the U.S. by
dialing 800-294-0997. Investors outside the U.S. may dial 402-220-9755. No
password is required for either number.

Quest Diagnostics Incorporated is the nation's leading provider of diagnostic
testing, information and services, providing insights that enable healthcare
professionals to make decisions that improve health. The company offers the
broadest access to diagnostic testing services through its national network of
laboratories and patient service centers, and provides interpretive consultation
through its extensive medical and scientific staff. Quest Diagnostics is the
leading provider of esoteric testing, including gene-based medical testing, and
provides advanced information technology solutions to improve patient care.
Additional company information is available at: www.questdiagnostics.com.

The statements in this press release which are not historical facts or
information may be forward-looking statements. These forward-looking statements
involve risks and uncertainties that could cause actual results and outcomes to
be materially different. Certain of these risks and uncertainties may include,
but are not limited to, competitive environment, changes in government
regulations, changing relationships with customers, payers, suppliers and
strategic partners and other factors described in the Quest Diagnostics
Incorporated 2003 Form 10-K and subsequent filings.


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