Investor Information

Common Stock
Quest Diagnostics Incorporated (ticker symbol: “DGX”) shares are listed on the New York Stock Exchange.

Quest Diagnostics is a component of several stock indices, including the S&P 500, Dow Jones Sustainability World Index and other social responsibility indices.

Options on Quest Diagnostics shares are traded on the Chicago Board Options Exchange.

Annual Meeting
The annual meeting of shareholders will be held on Tuesday, May 8, 2007, at The Waldorf-Astoria, 301 Park Avenue, New York, New York, at 10:30 A.M. Eastern Time. A proxy statement and annual report were mailed to shareholders of record as of March 12, 2007.

Additional Information
Corporate news releases, our Annual Report, Proxy Statement, Forms 10-K and 10-Q and other information about the company, including locations of facilities, are available
at Quest Diagnostics’ website at:
www.questdiagnostics.com

Address all inquiries to:
Investor Relations Department
Quest Diagnostics Incorporated
1290 Wall Street West
Lyndhurst, New Jersey 07071
(201) 393-5030
E-mail: investor@questdiagnostics.com

Transfer Agent and Registrar
National City Bank acts as transfer agent and registrar and dividend paying agent, and maintains all shareholder records for the company. If you have questions about the shares of Quest Diagnostics you own, wish to report a change of address or lost stock certificates or dividend checks, or would like to enroll in the company’s automatic dividend reinvestment or direct deposit program, please contact National City Bank directly:

National City Bank
Shareholder Services
P.O. Box 92301
Cleveland, Ohio 44193-0900
Phone: (800) 622-6757
E-mail:
shareholder.inquiries@nationalcity.com

Corporate Headquarters
1290 Wall Street West
Lyndhurst, New Jersey 07071
(201) 393-5000

Corporate Governance
Corporate governance guidelines, the code of business ethics and the charters of the committees of the Board are available at the Quest Diagnostics website. Any amendment to our code of business ethics, as well as any waivers from certain provisions of the code relating to our CEO and senior financial officers will be posted on our website.

Quest Diagnostics has included as Exhibit 31 to its Annual Report on Form 10-K for fiscal year 2006 filed with the Securities and Exchange Commission certificates of Quest Diagnostics’ Chief Executive Officer and Chief Financial Officer certifying the quality of the company’s public disclosure. Quest Diagnostics has submitted to the New York Stock Exchange (NYSE) a certificate of its Chief Executive Officer certifying that he is not aware of any violations by Quest Diagnostics of the NYSE corporate governance listing standards.

Inquiries to the company’s senior management or the Board of Directors may be sent via e-mail to:
seniormanagement@ questdiagnostics.com or
LeadIndependentDirector@
questdiagnostics.com

Trademarks
Quest Diagnostics, Quest, the Sun-Q logo and Nichols Institute are registered trademarks of Quest Diagnostics.

Care360, InSure, Blueprint for Wellness and Leumeta are trademarks of Quest Diagnostics.

Neither this report nor any statement contained herein is furnished in connection with any offering of securities or for the purpose of promoting or influencing the sale of securities.