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-      )
                                                       ------



                                                                          SERONO



Media  Release


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


                        NEW ADVANCE FOR INFERTILE COUPLES

        SERONO'S INNOVATIVE GONAL-F(R)  (FBM) PREFILLED PEN IS PHYSICIANS',
          NURSES' AND PATIENTS' PREFERRED CHOICE IN FERTILITY TREATMENT


GENEVA,  SWITZERLAND, MAY 3, 2004 - Serono (virt-x: SEO and NYSE: SRA) announced
today  that  the new GONAL-f(R) Filled-by-Mass (FbM) Prefilled Pen is considered
as the preferred choice for fertility treatment following an expert meeting held
this  weekend  in  Lisbon,  Portugal,  on  the initial experience of physicians,
nurses  and  patients  with  the  innovative  pre-filled  pen.

The  GONAL-f(R)  (FbM)  Prefilled Pen has recently been approved by the European
Commission,  the  Swiss and the Australian Authority. Through its combination of
an  accurate  and  easy-to-use  delivery  device  -  the  Prefilled  Pen  - with
GONAL-f(R) (FbM), the most consistent follicle-stimulating hormone available, it
represents  a  significant  advance  for  physicians,  nurses  and  patients  in
fertility  treatment.  Infertility  is  defined  as the inability of a couple to
achieve  pregnancy  after  one  year  of regular, unprotected intercourse and it
affects  according  to  WHO  around  60  -  80  million  people  worldwide.

In  a  phase  IIIb  study  that compared the GONAL-f(R) (FbM) Prefilled Pen with
another  pen  available  on  the  market,  twice as many of the treated patients
preferred  the  GONAL-f(R)  (FbM)  Prefilled  pen,  as it required less time for
training,  less  time  to prepare their daily injections and also gives patients
more  confidence  that they have injected the right dose of FSH. "The GONAL-f(R)
(FbM) Prefilled Pen ensures an accurate dosing and correct administration, as it
is ready-to-use and easy for patients to inject themselves, making the treatment
more acceptable for them", said Professor Dr. Christoph Keck from the Department
of  Obstetrics  and  Gynecology  of  the  University  of  Freiburg, Germany. (1)

In Australia, the country with most experience to date with the GONAL-f(R) (FbM)
Prefilled  Pen,  nurses  reported  a  significant reduction in the time to train
patients,  and  it  also  reduced patient confusion. "My nurses have told me how
much  less  time  they  have  to spend with patients and that fewer mistakes are
being  made due to incorrect dosing, as patients do not have to reconstitute the
medication  or to load a cartridge", explained Dr. Ric Porter, director from IVF
Australia's  Northshore  Unit  in  Chatswood.


-------------------------
1) Serono Data on File, Phase IIIb study, University of Freiburg, Germany.


                                                                             1/3

The  GONAL-f  (FbM)(R)  Prefilled  Pen  is  specifically  designed for fertility
treatment and is available in three multidose strengths, allowing individualized
dosing  in  Ovulation Induction and Assisted Reproductive Techniques. Delivering
the  most  consistent recombinant FSH - GONAL-f(R) (Filled-by-Mass) - it results
in  a  greater  and  more  predictable  control over ovarian stimulation (2) and
increases  treatment  efficiency  in  terms  of  a  reduction  of  the number of
stimulation days (3) (4), and the number of cancelled cycles (3).


ADDITIONAL  PRODUCT  INFORMATION
--------------------------------
GONAL-f(R)  Filled-by-Mass  (follitropin  alfa)  is  a  recombinant  human
follicle-stimulating  hormone,  which  is  equivalent  in  its  structure to the
naturally  occurring  human  FSH  in  the  body.  GONAL-f(R) (FbM) is the latest
advance which takes advantage of a standardized, highly consistent manufacturing
process  to  ensure  batch-to-batch  and  vial-to-vial  consistency  in  dosage,
resulting  in  the  most  consistent  FSH  and therefore in optimal control over
treatment  cycles.  GONAL-f(R)  is  used in clinical practice to treat infertile
women  and  men  with  low or lacking naturally occurring FSH. It is the world's
leading treatment for male and female infertility and is registered in more than
90  countries  around  the  world.

Infertility  is  defined as the inability of a couple to achieve pregnancy after
one  year  of  regular, unprotected intercourse (six months if the woman is over
35).  It  affects  about  10 million Europeans, representing about 10 percent of
couples in their childbearing years. Infertility is just as likely to be related
to  male  factors  as  female  factors,  which each account for about a third of
infertility  problems.  The remaining third are either a combination of male and
female  factors  or  are  unexplained.


SERONO  AND  FERTILITY  TREATMENT
---------------------------------
Serono,  the  world  leader  in  reproductive  health, is dedicated to providing
patient-friendly,  innovative products to help couples build families. Serono is
the only company to offer a full portfolio of fertility drugs for every stage of
the  reproductive cycle and recombinant versions of the three hormones needed to
treat  infertility:  GONAL-f(R) FbM (follitropin alfa), to stimulate the ovaries
and  produce  eggs;  Luveris(R)  (lutropin  alfa),  to  stimulate  follicular
development  in  women who are profoundly LH deficient; Cetrotide(R) (cetrorelix
acetate)  to  prevent  a  premature  ovulation; Ovitrelle(R) (choriogonadotropin
alfa),  to  help follicles mature and release eggs; and Crinone(R) (progesterone
gel),  to  help  establish  and  maintain  a  pregnancy.

For  more  information  on  infertility visit www.fertility.com and for Serono's
                                              -----------------
marketed  fertility  products  visit  www.serono.com.
                                      --------------

---------------------------
2) Hugues et al.; Improvement in consistency of response to ovarian stimulation
with recombinant human follicle hormone resulting from a new method for
calibrating the therapeutic preparation, RBM online, December 2002, Vol. 6, No.
2, pp 185 - 190

3) Tredway  et al.; Improvement of clinical profile with GONAL-f
Filled-by-Mass  in  ovulation  induction,  7th  Congress  of  the Latin American
Federation  of  the  Sterility  and  Fertility  Societies  (FLASEF), Montevideo,
Uruguay,  November  2002.

4) Balasch et al.; Outcome from consecutive assisted reproduction cycles in
patients treated with recombinant follitropin alfa filled-by-bioassay and those
treated with recombinant follitropin alfa filled-by-mass, RBM online, April
2004, Vol. 8, No. 4.


                                                                             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  over  30  projects  in development.

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).



                                       ###

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.

                                       ###



FOR MORE INFORMATION, PLEASE CONTACT:

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

                                 INVESTOR RELATIONS, USA:
                                 Tel:  +1 781 681 2552
                                 Fax:  +1 781 681 2912


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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 3, 2004                              By:  /s/  Francois Naef
                                              -----------------------------
                                              Name:  Francois Naef
                                              Title: Secretary