UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER
PURSUANT TO RULE 13a-16 OR 15d-16
UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of October 2004

Commission File Number: 001-31368

SANOFI-AVENTIS

174, avenue de France, 75013 Paris, FRANCE
(Address of principal executive offices)

     Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F.

Form 20-F þ                      Form 40-F o

     Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):                    

     Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):                    

     Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

Yes o                      No þ

     If “Yes” marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): 82-                   

Table of Contents

     On October 1, 2004, Sanofi-Aventis (formerly known as Sanofi-Synthelabo) issued the press release attached hereto as Exhibit 99.1 and caused the notice attached hereto as Exhibit 99.2 to be published in the Wall Street Journal. Each of Exhibits 99.1 and 99.2 is incorporated herein by reference.

     From October 1, 2004, the English language translation of the offer document, attached hereto as Exhibit 99.3, relating to the mandatory offer by Sanofi-Aventis to the shareholders of Hoechst AG will be available, free of charge, from BNP Paribas Securities Corp., The Equitable Tower, 787 Seventh Avenue, New York, New York 10019, United States of America and will be published on the Sanofi-Aventis website at: www.sanofi-aventis.com.

Exhibit List

SIGNATURES

     Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Exhibit Index