Exhibit 99

                                Merck & Co., Inc.
                                 One Merck Drive
                                  P.O. Box 100
                        Whitehouse Station, NJ 08889-0100




Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, D.C.  20549

March 21, 2002

Ladies and Gentlemen:

This will confirm that Merck & Co., Inc. (the "Company") has received a letter
from Arthur Andersen LLP ("Arthur Andersen") with respect to Arthur Andersen's
audit of the Company's consolidated financial statements for the year ended
December 31, 2001. Arthur Andersen's letter certifies that the audit was subject
to Arthur Andersen's quality control system for the U.S. accounting and auditing
practice to provide reasonable assurance that the engagement was conducted in
compliance with professional standards, that there was appropriate continuity of
Arthur Andersen personnel working on the audit, availability of national office
consultation, and availability of personnel at foreign affiliates of Arthur
Andersen to conduct the relevant portions of the audit.

Very truly yours,


Richard C. Henriques, Jr.
Vice President, Controller