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
---------------------


                   SERONO ANNOUNCES NEW SHARE BUY-BACK PROGRAM
                            FOR UP TO CHF 750 MILLION



GENEVA, SWITZERLAND, MAY 25, 2004 - Serono (virt-x: SEO and NYSE: SRA) announced
today that its Board of Directors has authorized the investment of up to CHF 750
million  for  the  purchase  of  Serono SA bearer shares in a new share buy-back
program.

"The  current share price represents an excellent opportunity for us to initiate
a  new share buy-back program," said Ernesto Bertarelli, Chief Executive Officer
of  Serono.  "This  initiative  reflects  our  commitment  to  promote long-term
shareholder  value."

The  authorization  applies  only  to  the  bearer  shares traded on virt-x, and
excludes  the  American Depositary Shares traded on the New York Stock Exchange.
It  is  subject  to the approval of the Swiss Takeover Board and the Swiss Stock
Exchange.

The share buy-back program is expected to start in June 2004 and will last for a
maximum  period  of five years.  The shares will be purchased on the open market
via  a  second  trading line, and subsequently cancelled.  This will result in a
reduction  of  the  number  of shares outstanding and thus increase earnings per
share.

Serono's  first  share  buy-back  program has fully utilized the CHF 500 million
allocated  and a total of 647,853 shares have been bought back as treasury stock
for  general  corporate  purposes.


                                                                             1/2

                                       ###
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 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:

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

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


                                                                             2/2

                                                                          SERONO


Media Release



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


                     SERONO SHAREHOLDERS APPROVE RESOLUTIONS
                            AT ANNUAL GENERAL MEETING



GENEVA, SWITZERLAND, MAY 25, 2004 - Serono (virt-x: SEO and NYSE: SRA)

Serono  announced that its shareholders have approved all the resolutions at the
Annual  General  Meeting  of  Shareholders, held today in Lausanne, Switzerland.

"2003 was a record year for our company with total revenues breaking through the
$2  billion  mark,"  said Ernesto Bertarelli, Chief Executive Officer of Serono.
"Each  of  our  businesses is growing well and I look forward for another strong
performance  in  2004."

Shareholders  approved  the  following  main  resolutions:

     - A cash dividend of CHF 123.9 million or $96.8 million(1)
     (2002: CHF 110.8 million or $81.4 million)
     -  Gross  dividend per bearer share of CHF 8.00 or $6.25
     (2002: CHF 7.00 or $5.15)
     -  Gross  dividend  per  American  Depositary Share of CHF 0.20 or $0.15625
     (2002:  CHF  0.175  or  $0.13)
     -  Gross dividend per registered share of CHF 3.20 or $2.50
     (2002: CHF 2.80 or  $2.06)

The  dividend  for  bearer shares will be paid as of May 28, 2004 net of the 35%
Swiss  withholding  tax. The total cash pay-out in Swiss Francs (CHF) represents
an  increase  of  11.8%  for  the  financial  year  2003 compared with 2002. The
dividend  pay-out  ratio  in  relation  to  earnings per share is 24.3% for 2003
compared  to  22.5%  for  2002.


_______________________________
(1)  All dollar figures are based on prevailing exchange rates. Final equivalent
US$ amounts may differ depending on exchange rates on the date of payment.


                                                                             1/3

Shareholders  have  approved  increasing  the  maximum amount of the conditional
capital to CHF 36,300,000 (1,452,000 bearer shares of a par value of CHF 25) for
option  and/or convertible loans and to CHF 18,825,000 (753,000 bearer shares of
a  par value of CHF 25) for a stock option plan.  In addition, shareholders have
approved  the  renewal  of the authorization to increase capital by a maximum of
CHF  35,000,000  (1,400,000 bearer shares of a par value of CHF 25) for a period
of  two  years.

Shareholders  approved the re-election for one year of all members of the Board:

     Mr. Georges Muller (Chairman)
     Mr. Ernesto Bertarelli (Vice Chairman and Managing Director)
     Mr. Pierre  E.  Douaze
     Mr. Bernard Mach
     Mr. Sergio Marchionne
     Mr. Jacques Theurillat
     Mr. Hans Thierstein.

Shareholders also approved the election of a new Director:

     Mr Patrick Gage

The Annual Report and Accounts for 2003 were approved.



                                       ###


                                                                             2/3

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 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:

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

MEDIA RELATIONS, USA:          INVESTOR RELATIONS, USA:
Tel:  +1 781 681 2340          Tel:  +1 781 681 2552
Fax:  +1 781 681 2935          Fax:  +1 781 681 2912
http://www.seronousa.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)



May 25, 2004                       By:  /s/  Francois Naef
                                        -----------------------
                                        Name:  Francois Naef
                                        Title: Secretary