SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549
                                    ________

                                    FORM 6-K

                        REPORT OF FOREIGN PRIVATE ISSUER
                      PURSUANT TO RULE 13A-16 OR 15D-16 OF
                       THE SECURITIES EXCHANGE ACT OF 1934

                         For the month of November, 2004

                                  Serono S.A.
                  --------------------------------------------
                              (Registrant's Name)

                            15 bis, Chemin des Mines
                                Case Postale 54
                                CH-1211 Geneva 20
                                  Switzerland
                    ----------------------------------------
                    (Address of Principal Executive Offices)

                                    1-15096
                  --------------------------------------------
                              (Commission File No.)

     (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 
               ---            ---
     (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       No  X
         ---      ---

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



Serono                                                        Nautilus
                                                               Biotech


Media Release

FOR IMMEDIATE RELEASE
---------------------


                          SERONO AND NAUTILUS BIOTECH
              SIGN WORLDWIDE AGREEMENT TO DEVELOP AND COMMERCIALIZE
                        A NEXT-GENERATION GROWTH HORMONE


GENEVA, SWITZERLAND AND PARIS, FRANCE - NOVEMBER 15, 2004 -
Serono  (virt-x:  SEO  and  NYSE:  SRA)  and  protein evolution company Nautilus
Biotech (Private) announced today that they have signed an agreement under which
Serono  and  Nautilus will work together to develop the next-generation of human
growth hormone, with improved biological, pharmacological and clinical profiles.
This  improved  version  of  human  growth  hormone  would  allow  less frequent
injections  of  this  therapeutic protein which is currently administered daily.

Under  the  terms  of the agreement, Serono will receive an exclusive license to
develop  the  next-generation  human  growth  hormone and an exclusive option to
license  exclusive  worldwide  rights to develop, manufacture, and commercialize
improved  variants  of  the  protein  generated by Nautilus's rational evolution
technology,  a  process  mimicking  natural evolution.  In return, Nautilus will
receive  an  initial fee and potential milestone payments related to development
progress,  regulatory  submissions  and  approvals.  If  a new version of growth
hormone is successfully developed and registered worldwide, and Serono exercises
its  option  right,  the  aggregate amount of these payments could reach Euro 19
million.  Nautilus  will  also  receive  undisclosed  royalties  on sales of the
improved  protein.

"Serono  has  a  long-term  commitment  to  people  with endocrine and metabolic
disorders  requiring growth hormone treatment", said Tim Wells, Senior Executive
VP  Research  of  Serono.  "We believe that the rational evolution technology of
Nautilus  represents  a  promising  approach to generate growth hormone variants
with  great  potential  to  deliver  improved  patient  care."

"Serono  has  an  impressive  track  record  in the development and marketing of
protein  therapeutics,"  said  Manuel  Vega  CEO  of  Nautilus Biotech. " We are
confident  that  in Serono we have found a strong and committed partner to fully
exploit  the power of our protein improvement technology and to develop this new
product  as  a  competitive improvement to currently marketed alternatives. This
agreement  with Serono, a world leader in protein pharmaceuticals, validates our
strategy  and  business  model  in  the  area  of  biopharmaceuticals".


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                                      #####
Serono 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 March 25, 2004. 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,  and government regulations
limiting  our  ability  to  sell  our  products. Serono 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.

                                      #####
ABOUT SERONO
Serono  is  a  global  biotechnology leader. The Company has eight biotechnology
products,  Rebif(R),  Gonal-F(R),  Luveris(R),  Ovidrel(R)/Ovitrelle(R),
Serostim(R),  Saizen(R),  Zorbtive(TM) and Raptiva(R) . 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.  Currently,  there  are  approximately 30
ongoing  development  projects.

In  2003,  Serono  achieved  worldwide revenues of US$2,018.6 million, and a net
income  of  US$390.0 million, making it the third largest biotech company in the
world. Its products are sold in over 90 countries. 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).

ABOUT NAUTILUS BIOTECH
Nautilus  is  focused  on  improving  and  developing  next  generation  protein
pharmaceuticals.  Using  its  proprietary  and unique technologies, Nautilus has
generated a pipeline of improved therapeutic protein molecules with single amino
acid  substitutions;  and  has  IP claims on 20 improved cytokines. Long lasting
interferon  alpha and interferon beta, presently in preclinical development, are
Nautilus'  lead  molecules.  Nautilus  Biotech  is  a privately owned, VC backed
company,  founded  in  late  1999.  More about Nautilus: www.nautilusbiotech.com
                                                         -----------------------

FOR MORE INFORMATION, PLEASE CONTACT:

SERONO IN GENEVA, SWITZERLAND:

CORPORATE MEDIA RELATIONS:     CORPORATE INVESTOR RELATIONS:
Tel: +41 22 739 36 00          Tel: +41 22 739 36 01
Fax: +41 22 739 30 85          Fax: +41 22 739 30 22
http://www.serono.com          Reuters: SEO.VX / SRA.N
---------------------          Bloomberg: SEO VX / SRA  US

SERONO, INC., ROCKLAND, MA:

MEDIA RELATIONS, USA:       INVESTOR RELATIONS, USA:
Tel: +1 781 681 2486        Tel: +1 781 681 2552
Fax: +1 781 681 2935        Fax: +1 781 681 2912
http://www.seronousa.com
------------------------

NAUTILUS BIOTECH:

Jon Watts, VP Business Development                   Manuel Vega, CEO
jwatts@nautilusbiotech.com                           mvega@nautilusbiotech.com
--------------------------                           -------------------------
Tel: +44.1488.670.130                                Tel: +33. (0) 1.60.87.54.60


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                                   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.



                                   SERONO S.A.
                                   a Swiss corporation
                                   (Registrant)



November 15, 2004                  By:    /s/ Francois Naef
                                          --------------------
                                   Name:  Francois Naef
                                   Title: Secretary