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):       

Note: Regulation S-T Rule 101(b)(1) only permits the submission in paper of a Form 6-K if submitted solely to provide an attached annual report to security holders.

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):       

Note: Regulation S-T Rule 101(b)(7) only permits the submission in paper of a Form 6-K if submitted to furnish a report or other document that the registrant foreign private issuer must furnish and make public under the laws of the jurisdiction in which the registrant is incorporated, domiciled or legally organized (the registrant's "home country"), or under the rules of the home country exchange on which the registrant's securities are traded, as long as the report or other document is not a press release, is not required to be and has not been distributed to the registrant's security holders, and, if discussing a material event, has already been the subject of a Form 6-K submission or other Commission filing on EDGAR.

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-     .

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The Registrant's press release regarding the announcement of the adoption, by the Committee for Medicinal Products for Human Use ("CHMP"), of a negative opinion, recommending to the European Medicines Agency's ("EMA") the refusal of the marketing authorization for Defibrotide to treat and prevent hepatic veno-occlusive disease ("VOD") in adults and children undergoing hematopoietic stem cell transplantation therapy. Gentium remains convinced of the favourable benefit/risk profile of Defibrotide, and plans to appeal the EMA's decision and request a re-examination of the CHMP opinion.

This report and the exhibit attached thereto are incorporated by reference into the registration statements of Gentium S.p.A. on Forms F-3: File No. 333-135622, File No. 333-137551, File No. 333-138202, File No. 333-139422, File No. 333-141198, and File No. 333-174575 and on Forms S-8: File No. 333-137534, File No. 333-146534 and File No. 333-181171.

Exhibit		Description
1		Press release, dated March 22, 2013.

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.

		Gentium S.p.A. (Registrant)
Date: March 22, 2013		/s/ SALVATORE CALABRESE Salvatore Calabrese Chief Financial Officer and Senior VP, Finance