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 October, 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
PARATEK
PHARMACEUTICALS


MEDIA RELEASE


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


                SERONO AND PARATEK PHARMACEUTICALS IN PARTNERSHIP
            TO DEVELOP A NOVEL ORAL TREATMENT FOR MULTIPLE SCLEROSIS


GENEVA, SWITZERLAND AND BOSTON, USA - OCTOBER 27, 2004 -
Serono  (virt-x:  SEO and NYSE: SRA) and Paratek Pharmaceuticals, Inc. announced
today  that  they  have  entered  into  an  agreement  to  discover, develop and
commercialize  an  orally-available  disease  modifying  treatment  for multiple
sclerosis  (MS).

During the initial phase of their collaboration, Paratek and Serono will seek to
identify  for clinical development novel tetracycline derivatives from a library
of  non-antibiotic  lead  compounds  discovered  by  Paratek  chemists.  Orally
administered minocycline (an antibiotic tetracycline) was reported in a recently
published  clinical  study  to  have  a  therapeutic benefit in the treatment of
patients  with  relapsing-remitting  MS(1).  The favorable safety profile of the
tetracycline  class is well documented, with a more than 30-year track record in
the  marketplace.  Serono  will be responsible for the worldwide development and
commercialization  of  compounds  arising  from  the  collaboration.  No  orally
administered  disease-modifying  drug is currently approved for the treatment of
MS.

"This  partnership  with  Paratek  reflects our long-term commitment to patients
with  multiple  sclerosis",  said  Tim  Wells,  Head  of  Research  of  Serono.
"Non-antibiotic  tetracycline-derived  compounds  represent a promising approach
for  the  development of orally available treatments for multiple sclerosis.  We
are very pleased to be working with Paratek, which has considerable expertise in
this area and has already identified a number of very promising compounds."

"Serono's  commitment  to  multiple  sclerosis  and  their  extensive  research
expertise  in  the  fields  of  neurology, immunology and inflammation were very
attractive  to Paratek.  This collaboration validates the use of our proprietary
tetracycline chemistry expertise to create improved novel compounds specifically
targeting  promising  new  uses,"  said  Thomas  J. Bigger, President and CEO of
Paratek  Pharmaceuticals.


-------------------------
(1)  Metz  LM et al. Minocycline reduces gadolinium-enhancing magnetic resonance
imaging lesions in multiple sclerosis. Annals of Neurology 2004; 55(5):756


                                                                             1/3

Under  the terms of the agreement, Paratek will receive an initial cash payment,
a  loan convertible into Paratek stock, research funding and potential milestone
payments related to development progress and regulatory milestones.  In addition
to  upfront  consideration,  Paratek  would  receive USD 38 million in milestone
payments  from  Serono  for  the  first product to be successfully developed and
registered  in  MS.  Additional  drugs and indications developed would result in
further  payments  to  Paratek.  Paratek  will  receive undisclosed royalties on
product  sales  should  a  product  reach  the  market.

Preclinical  data on three non-antibacterial tetracycline derivatives covered by
this  agreement  will  be  presented today at Neuroscience 2004, the Society for
Neuroscience's  34th  Annual  Meeting  in  San  Diego.



ABOUT MULTIPLE SCLEROSIS
------------------------

Multiple  sclerosis  is  a chronic, inflammatory condition of the nervous system
and  is  the  most  common, non-traumatic, neurological disease in young adults.
Multiple  sclerosis may affect approximately two million people worldwide. While
symptoms  can  vary,  the  most  common  symptoms  of multiple sclerosis include
blurred vision, numbness or tingling in the limbs and problems with strength and
coordination.  The  relapsing  forms  of multiple sclerosis are the most common.


                                      ###


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  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.


                                      ###


                                                                             2/3

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 PARATEK PHARMACEUTICALS
-----------------------------

PARATEK  PHARMACEUTICALS, INC. is engaged in the discovery and commercialization
of  new  therapeutics  that  treat serious and life-threatening diseases, with a
particular  focus  on  the  growing  worldwide problem of antibiotic resistance.
Paratek's  lead  programs  are  advancing novel compounds that can circumvent or
block  bacterial  resistance,  as  well  as  drugs that can prevent infection by
interfering  with  Multiple  Adaptational Response (MAR) mechanisms in bacteria.
Out  of  these  efforts,  Paratek has discovered a new class of antibiotics, the
aminomethylcyclines  that  target  the need for new and potent antibacterials to
overcome  the  problem  of  rapidly growing bacterial resistance.  The Company's
lead  antibiotic  clinical  candidate,  BAY 73-7388, the first product from this
class,  is  being developed in a collaborative partnership with Bayer HealthCare
AG  for  the  treatment  of  serious  infections.

Outside  the  antibacterial  therapeutic  area,  Paratek has also established an
internal  effort  to  exploit  its  novel families of compounds and their unique
mechanism  of  action  in  selected  anti-inflammatory  and  neurodegenerative
conditions.  Paratek  has  an  active chemical synthesis effort to produce novel
and  diverse  small  molecules,  with  the  goal of developing non-antibacterial
products with improved activity in serious diseases based upon a growing body of
clinical  and  basic  research  supporting  this  approach.

Paratek  is privately held and headquartered in Boston, Massachusetts, USA.  For
more information, visit Paratek's website at www.paratekpharm.com.
                                             --------------------


FOR MORE INFORMATION, PLEASE CONTACT:

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


SERONO, INC., ROCKLAND, MA
MEDIA RELATIONS:                              INVESTOR RELATIONS:
Tel. +1 781 681 2340                          Tel. +1 781 681 2552
Fax: +1 781 681 2935                          Fax: +1 781 681 2912
http://www.seronousa.com
------------------------


PARATEK PHARMACEUTICALS, INC, BOSTON, MA
INVESTOR RELATIONS:                           MEDIA RELATIONS:
Kate Boxmeyer                                 Justin Jackson
Tel. +1 617.275.0040 x238                     Tel. +1 212.213.0006
E-mail: kboxmeyer@paratekpharm.com            E-mail: jjackson@burnsmc.com
        --------------------------                    --------------------


                                                                             3/3

                                   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)



October 27, 2004                            By:    /s/ Francois Naef
                                                   --------------------------
                                            Name:  Francois Naef
                                            Title: Secretary