March 20, 2003

Dear Stockholders:

It is my pleasure to invite you to Merck’s 2003 Annual Meeting of Stockholders. We will hold the meeting on Tuesday, April 22, 2003, at 2:00 p.m., in the Edward Nash Theatre at Raritan Valley Community College, Route 28 and Lamington Road, North Branch, New Jersey. During the Annual Meeting, we will discuss each item of business described in the Notice of Annual Meeting and Proxy Statement and give a report on the Company’s business operations. There will also be time for questions.

This booklet includes the Notice of Annual Meeting and Proxy Statement. The Proxy Statement provides information about Merck in addition to describing the business we will conduct at themeeting.

We hope you will be able to attend the Annual Meeting. Whether or not you expect to attend, please vote your shares using any of the following methods: vote by telephone or the Internet, as described in the instructions you receive; sign and date the proxy card or voting instruction card and return it in the prepaid envelope; or vote in person at the meeting.

Sincerely,

Go to Notice of Annual Meeting of Stockholders