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

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 December

Commission File Number 1-15096

Serono S.A.
(Translation of registrant’s name into English)

15 bis, Chemin des Mines
Case Postale 54
CH-1211 Geneva 20
Switzerland
(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of 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):  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)(7):  o

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

Media Release

FOR IMMEDIATE RELEASE

MERCK KGAA: EUROPEAN ANTITRUST AUTHORITIES
CLEAR ACQUISITION OF SERONO

Geneva, Switzerland, — December 18, 2006 — Serono (virt-x: SEO and NYSE: SRA) has today been informed that Merck KGaA of Darmstadt, Germany has published the following press release:

The European Commission has approved the planned acquisition of Serono SA by Merck KGaA without any restrictions. The transaction already received U.S. antitrust approval on October 30, 2006.

Following the closing of the agreement with the Bertarelli family, which remains planned for early January 2007, Merck will make a public tender offer under Swiss law to the shareholders of Serono for Sfr 1,100 per share.

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Forward-looking statements
Some of the statements in this press release are forward looking. Such statements are inherently subject to known and unknown risks, uncertainties and other factors that may cause actual results, performance or achievements of Serono S.A. and affiliates to be materially different from those expected or anticipated in the forward-looking statements. Forward-looking statements are based on Serono’s current expectations and assumptions, which may be affected by a number of factors, including those discussed in this press release and more fully described in Serono’s Annual Report on Form 20-F filed with the U.S. Securities and Exchange Commission on February 28, 2006. These factors include any failure or delay in Serono’s ability to develop new products, any failure to receive anticipated regulatory approvals, any problems in commercializing current products as a result of competition or other factors, our ability to obtain reimbursement coverage for our products, the outcome of any government investigations and litigation.  Serono is providing this information as of the date of this press release, and has no responsibility to update the forward-looking statements contained in this press release to reflect events or circumstances occurring after the date of this press release.

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About Serono
Serono is a global biotechnology leader.  The Company has eight biotechnology products, Rebif®, Gonal-f®, Luveris®, Ovidrel®/Ovitrelle®, Serostim®, Saizen®, Zorbtive™ and Raptiva®.  In addition to being the world leader in reproductive health, Serono has strong market positions in neurology, metabolism and growth and has recently entered the psoriasis area.  The Company’s research programs are focused on growing these businesses and on establishing new therapeutic areas, including oncology and autoimmune diseases.

In 2005, Serono, whose products are sold in over 90 countries, achieved worldwide revenues of US$2,586.4 million.  Reported net loss in 2005 was US$106.1 million, reflecting a charge of US$725 million taken relating to the settlement of the US Attorney’s Office investigation of Serostim.  Excluding this charge as well as other non-recurring items, adjusted net income grew 28.4% to US$565.3 million in 2005.  Bearer shares of Serono S.A., the holding company, are traded on the virt-x (SEO) and its American Depositary Shares are traded on the New York Stock Exchange (SRA).

For more information, please contact:

Corporate Media Relations:		Corporate Investor Relations:
Tel:	+41 22 414 36 00	Tel:	+41 22 414 36 01
Fax:	+41 22 414 30 85	Fax:	+41 22 414 30 22
http://www.serono.com		Reuters: SEO.VX / SRA.N
		Bloomberg: SEO VX / SRA US
Media Relations, USA:		Investor Relations, USA:
Tel:	+1 781 681 2340	Tel:	+1 781 681 2552
Fax:	+1 781 681 2935	Fax:	+1 781 681 2912
http://www.seronousa.com

 

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SIGNATURE

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.

			SERONO S.A.,
			a Swiss corporation
			(Registrant)
Date	December 18, 2006		By:	/s/ Stuart Grant
			Name: Stuart Grant
			Title: Chief Financial Officer