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 May, 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-______)



                                                                [GRAPHIC OMITED]



Media  Release


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


                SERONO ANNOUNCES LAUNCH OF REBIJECT II(TM) DEVICE
               FOR MULTIPLE SCLEROSIS PATIENTS ON REBIF(R) THERAPY

      REBIJECT II(TM) MAKES SELF-INJECTION OF REBIF(R) EVEN MORE CONVENIENT


GENEVA, SWITZERLAND, MAY 6, 2004 - Serono (virt-x: SEO and NYSE: SRA), announced
today the launch of its new Rebiject II(TM) auto-injector, a device specifically
designed to make self-injection of Rebif(R) (interferon beta-1a) more convenient
for  multiple  sclerosis  (MS)  patients  on  Rebif(R)  therapy.

"Rebiject  II(TM)  is  another  example  of Serono's commitment to improving the
quality  of  life of people with multiple sclerosis," said Franck Latrille, Head
of  Product  Development  at  Serono.  "Rebiject  II(TM)  should  make  Rebif(R)
administration  easier  and  help  to  support treatment compliance for multiple
sclerosis  patients."

A study conducted in 115 patients with MS on Rebif(R) therapy showed that 71% of
these  patients  found  the  new  Rebiject II(TM) was better than their previous
injection  method.  Patient  feedback  indicated  that injections using Rebiject
II(TM)  were  less  painful,  and that the new Rebiject II(TM) was easier to use
than  the  previous  Rebiject  mini(TM)  auto-injector  or  manual  injection.

Rebiject  II(TM)  is  specifically designed for use with the Rebif(R) pre-filled
syringe.  It provides several advantages compared to the previous auto-injector.
These  advantages  are:
     -    Fewer  steps are needed to inject - no need to remove the plunger from
          the  pre-filled  syringe
     -    An adjustable needle depth regulator to allow the injector be tailored
          to  each  patient
     -    A  visual  signal  to  show patients that the injection has been fully
          delivered
     -    A  safety  mechanism  to  minimize the chance of accidental activation
          that  could  result  in  loss  of  medication
     -    Better design making it easier to handle for patients suffering of MS,
          with  a  square,  non-rolling,  non-slip  rubber  grip.

Serono  was the first company to introduce an auto-injector for MS patients with
the  introduction  of  Rebiject  mini(TM).  Now,  with  Rebiject  II(TM), Serono
continues to lead the way in developing patient-friendly injection devices, with
advanced  functionality.


                                                                             1/3

The  Rebiject  II(TM)  auto-injector,  combined  with  the  recently  announced
availability  of  the  new  29  gauge  needle  Rebif(R)  pre-filled syringe (the
thinnest  needle  available  on  a  ready-to-use  pre-filled  syringe), provides
patients  with  state-of-the-art  technology  that  is  designed to maximize the
benefits  of  Rebif(R)  therapy.

The  new Rebiject II(TM) auto-injector is currently being launched in Europe and
Canada  as  well  as  in certain countries of Asia, Latin America and the Middle
East.  Rebiject II(TM) is expected to be available worldwide by the end of 2004.


ABOUT  REBIF(R)

Rebif(R)  (interferon  beta-1a)  is  a  disease-modifying  drug  used  to  treat
relapsing  forms  of  multiple  sclerosis  and is similar to the interferon beta
protein  produced by the human body. Interferon helps modulate the body's immune
system,  fight  disease  and  reduce  inflammation.

Rebif(R),  which  was  approved  in  Europe  in  1998  and in the US in 2002, is
registered  in  more than 80 countries worldwide. In the United States, Rebif(R)
is  co-marketed  by  Serono,  Inc.  and  Pfizer Inc. Rebif(R) has been proven to
reduce MRI lesion activity and area, reduce the frequency of relapses, and delay
the  progression  of  disability.  Rebif(R)  is available in a 22 mcg and 44 mcg
ready-to-use  pre-filled syringe and can be stored at room temperature for up to
30  days  if  a  refrigerator  is  not  available.


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.


                                       ###
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 seven recombinant
products,  Rebif(R),  Gonal-F(R),  Luveris(R),  Ovidrel(R)/Ovitrelle(R),
Serostim(R), Saizen(R) and Zorbtive(TM) (Luveris(R) is not approved in the USA).
In  addition to being the world leader in reproductive health, Serono has strong
market  positions  in  neurology,  metabolism and growth. 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).


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       Fax:  +41-22-739  30  22
http://www.serono.com          Reuters: SEO.VX / SRA.N
---------------------          Bloomberg: SEO VX / SRA US

SERONO, INC., ROCKLAND, MA:
INVESTOR  RELATIONS:
Tel.  +1 781 681 2552
Fax:  +1 781 681 2912
www.seronousa.com
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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)



May  6,  2004                      By:  /s/ Francois Naef
                                        -------------------------------
                                        Name:  Francois  Naef
                                        Title: Secretary