UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Commission File Number: 001-31368

SANOFI-SYNTHÉLABO

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  x            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  x

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

April 5th , 2004

Sanofi-Synthélabo’s Offer for Aventis

Sanofi-Synthélabo announces the filing today of the notification of its offer for Aventis with the U.S. Federal Trade Commission (FTC) under the Hart-Scott-Rodino Antitrust Improvements Act of 1976.

In accordance with article 7 of the COB rule no. 2002-04, this document was transmitted to the “Autorité des marchés financiers” (AMF) before its publication.

Important Information:  In connection with the proposed acquisition of Aventis, Sanofi-Synthelabo has filed a registration statement on Form F-4 (File no. 333-112314) and will file additional documents with the United States Securities and Exchange Commission (SEC) Investors are urged to read the registration statement and any other relevant documents filed with the SEC, including all amendments, because they contain important information. Free copies of the registration statement, as well as other relevant documents filed with the SEC, may be obtained at the SEC’s web site at www.sec.gov. At the appropriate time, transaction-related documents may be obtained for free from Sanofi-Synthelabo.

In France, holders of Aventis securities are requested, with respect to the offer, to refer to the prospectus (note d’information), which has been granted visa number 04-0090 by the Autorité des marchés financiers (“AMF”) and which is available on the website of the AMF (www.amf-france.org) and without cost from: BNP Paribas Securities Services, GIS-Emetteurs, Service Logistique, Les Collines de l’Arche, 75450 Paris Cedex 9.

On March 11, 2004, Sanofi-Synthelabo issued an offer prospectus in accordance with German law, which is the only document applicable in connection with the public offer made by Sanofi-Synthélabo to holders of Aventis ordinary shares located in Germany (the “German Offer”). Any decision to tender Aventis ordinary shares in exchange for Sanofi-Synthélabo ordinary shares under the German Offer must be taken exclusively with regard to the terms and conditions of the German Offer, as well as with regard to the information included in the offer prospectus issued in Germany.

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.