UNITED STATES
                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                                   FORM 25

                 NOTIFICATION OF REMOVAL FROM LISTING AND/OR
                   REGISTRATION UNDER SECTION 12(B) OF THE
                       SECURITIES EXCHANGE ACT OF 1934

                   Commission File Number     000-51341
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Gentium S.p.,A., American Stock Exchange
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(Exact name of Issuer as specified in its charter, and name of Exchange where
                    security is listed and/or registered)

Piazza XX Settembre 2, 22079 Villa Guardia (Como), Italy Tel: +39 031 385111
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 (Address, including zip code, and telephone number, including area code, of
                    Issuer's principal executive offices)

Ordinary Shares, par value (euro)1.00 per share (not for trade, but only in
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connection with the American Depositar y Shares)*
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                     (Description of class of securities)

Please place an X in the box to designate the rule provision relied upon to
strike the class of securities from listing and registration:

|_|   l7CFR240.12d2-2(a)(1)

|_|   l7CFR240.12d2-2(a)(2)

|_|   l7CFR240.12d2-2(a)(3)

|_|   l7CFR240.12d2-2(a)(4)

|_| Pursuant to 17 CFR 240.12d2-2(b), the Exchange has complied with its rules
to strike the class of securities from listing and/or withdraw registration on
the Exchange(1)

|X| Pursuant to 17 CFR 240.12d2-2(c), the Issuer has complied with the rules of
the Exchange and the requirements of 17 CFR 240.12d2-2(c) governing the
voluntary withdrawal of the class of securities from listing and registration on
the Exchange

Pursuant to the requirements of the Securities Exchange Act of 1934, Gentium
S.p.A. (Name of Issuer or Exchange) certifies that it has reasonable grounds to
believe that it meets all of the requirements for filing the Form 25 and has
caused this notification to be signed on its behalf by the undersigned duly
authorized person.

May 15, 2006                                                By /s/ Cary Grossman
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   Date                                                             Name
           Executive Vice-President and Chief Financial Officer
           ----------------------------------------------------
                                     Title

   (1) Form 25 and attached Notice wit) be considered compliance with the
   provisions of 17 CFR 240.l9d-l as applicable. See General Instruction

            SEC 1654(03-06) Persons who respond to the collection of
             information contained in this form are not required to
             respond unless the form displays a currently valid OMB
                                 control number.

*     American Depositary Shares representing the Ordinary Shares are registered
      under the Securities Act of 1933, as amended, pursuant to a separate
      Registration Statement on Form F-6 (Registration No. 333-125663), as
      amended, originally filed with the Securities and Exchange Commission on
      June 9, 2005, and accordingly, are exempt from registration under Section
      12(b) of the Securities Exchange Act of 1934, as amended, pursuant to rule
      12g3-2(c) thereunder.