Quest Diagnostics Incorporated , the nation's leading provider of diagnostic testing, information and services, announced that it is scheduled to speak at the Thomas Weisel Partners Tailwinds Conference on Friday, September 9, 2005, at The Four Seasons Hotel in Boston, Massachusetts. The Quest Diagnostics presentation is scheduled to begin at 9:45 a.m. Eastern Time.

The presentation will be webcast live during the conference and will be available to registered investors on the following site: http://www.veracast.com/webcasts/twp/hc2005/52304122.cfm and to the public on: http://www.questdiagnostics.com/. In addition, the archived webcast will be available for 30 days starting four hours after the presentation.

Quest Diagnostics is the leading provider of diagnostic testing, information and services that patients and doctors need to make better healthcare decisions. 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 a pioneer in developing innovative new diagnostic tests and advanced healthcare information technology solutions that help improve patient care. Additional company information is available at: http://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 2004 Form 10-K and subsequent filings.

SOURCE: Quest Diagnostics Incorporated

CONTACT: Laure Park, Investors, +1-201-393-5030, or Gary Samuels, Media,
+1-201-393-5700, both of Quest Diagnostics Incorporated

Web site: http://www.questdiagnostics.com/