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 March, 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
---------------------



                REBIF(R) NOW AVAILABLE WITH THE THINNEST NEEDLE
                      IN A READY-TO-USE PRE-FILLED SYRINGE
                    FOR THE TREATMENT OF MULTIPLE SCLEROSIS



GENEVA,  SWITZERLAND,  MARCH  30,  2004  -  Serono  (virt-x: SEO and NYSE: SRA),
announced  today  the  launch  of  its new 29 gauge-needle pre-filled syringe of
Rebif(R),  the  thinnest  needle  in  a  ready to use pre-filled syringe for the
treatment  of  multiple  sclerosis.

"The  new Rebif(R) pre-filled syringe illustrates once again Serono's commitment
to  improving  patients' quality of life," said Franck Latrille, Serono's Senior
Executive Vice President Global Product Development. "Having Rebif(R) in a ready
to  use  pre-filled  syringe  with such a thin needle will make its subcutaneous
administration  easier  for patients. In addition to improving patients' quality
of  life,  easy  administration is a key factor in ensuring a good compliance to
treatment."

A study conducted in Denmark showed that 86% of Rebif(R) -treated patients found
that  injections  were  easier  and  less  painful  using  the  new  needle. The
pre-filled  syringe  of  Rebif(R)  with  the new needle is available in the same
dosages  as the previous version and will continue to carry the same indication.
It  is currently being launched in Europe and will be available worldwide by the
end  of  2004.


                                                                             1/2

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-promoted  by  Serono  and  Pfizer  Inc.

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.

                                       ###

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: SEOZ.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
-----------------


                                                                             2/2

                                   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)



March 30, 2004                           By:     /s/  Allan  Shaw
                                                 -----------------------------
                                         Name:   Allan Shaw
                                         Title:  Chief Financial Officer