FORM 6-K
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                            Report of Foreign Issuer

                      Pursuant to Rule 13a-16 or 15d-16 of
                       the Securities Exchange Act of 1934

                        For the month of September, 2005

                        Commission File Number: 333-07654


                                  ENDESA, S.A.
                 (Translation of Registrant's Name into English)

                              Ribera del Loira, 60
                               28042 Madrid, Spain
                     (Address of principal executive office)


        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):
                                 Yes [ ] No [X]

         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):
                                 Yes [ ] No [X]

                        Indicate by check mark whether by
             furnishing the information contained in this Form, the
     Registrant 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): N/A
                                                        ---

[LOGO OMITTED]

                                                     Madrid, 15th September 2005




Dear             ,

I am writing to update you on  Endesa's  response to the  hostile  tender  offer
launched by Gas Natural  (the  "Offer") and inform you of what to expect from us
in the coming weeks.

As you will have  seen,  Endesa's  Board of  Directors  has  rejected  the offer
unanimously based on the conviction that it is grossly inadequate and not in the
best interests of our  shareholders.  We strongly believe  Endesa's  stand-alone
Strategic Plan will deliver superior value to our  shareholders  compared to the
(highly  uncertain) value implied by the Offer.  Furthermore,  Endesa's Board of
Directors is confident of achieving this superior value without the  significant
risk entailed by the proposed transaction.

We are  currently  preparing  a  comprehensive  response  to the  offer and will
contact you shortly to schedule a time to discuss it in person. In the meantime,
we ask for your continued support and confidence in the strong positive momentum
of the Endesa story.

Yours sincerely,


Rafael Miranda
CEO




                                   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.

                                                 ENDESA, S.A.

Dated: September 15th , 2005            By: /s/ Alvaro Perez de Lema
                                        ---------------------------------------
                                        Name: Alvaro Perez de Lema
                                        Title: Manager of North
                                        America Investor Relations