This Amendment No. 1 (the “First Amendment”) amends the initial Schedule 13D (the “Schedule 13D”) filed on February 29, 2008, with the Securities and Exchange Commission (the “SEC”), by the Reporting Persons (as defined in the Schedule 13D), with respect to Class D Shares par value 10 Argentine pesos per share (the “Class D Shares”) and American Depositary Shares (“ADSs”) of YPF Sociedad Anónima (“YPF” or the “Issuer”), with each ADS representing one Class D Share. Capitalized terms used but not otherwise defined in this First Amendment have the meaning ascribed to such terms in the Schedule 13D.

Item 3.

As discussed in the Schedule 13D, Petersen SA assigned to Repsol its right to receive its share of the extraordinary dividend declared by the shareholders’ meeting of YPF on February 7, 2008, to be paid on or after February 29, 2008, pursuant to the terms of the Dividend Agreement. Such dividend was distributed on February 29, 2008, and paid to Repsol in the amount of Ps.630,574,801, which, pursuant to the currency conversion mechanism set forth in the Dividend Agreement (as described in the Schedule 13D), was equivalent to US$199,675,364 or US$1,474,636 less than the amount required to be paid under the SPA (i.e., US$201,150,000), and, therefore, in accordance with the terms of the Dividend Agreement, the outstanding principal amount under the Seller Credit Agreement will be increased by such difference.

(d) The description contained herein supplements Item 4 in the Schedule 13D and should be read in connection therewith.

On March 7, 2008, pursuant to the Shareholders’ Agreement, at a shareholders meeting of YPF, Mr. Enrique Eskenazi, Mr. Sebastián Eskenazi, and Mr. Matías Eskenazi Storey were appointed directors of YPF, and Mr. Ezequiel Eskenazi Storey was appointed an alternate director of YPF. On the same date, the Board (including Mr. Sebastián Eskenazi, Mr. Enrique Eskenazi, and Mr. Matías Eskenazi Storey) (i) appointed Mr. Sebastián Eskenazi Chief Executive Officer of YPF, Mr. Enrique Eskenazi Non-Executive Vice President, and Mr. Antonio Gomis, a representative designated by Repsol, Chief Operating Officer; and (ii) appointed Mr. Sebastián Eskenazi President of the Executive Committee of YPF.

(g) On March 7, 2008, at the shareholders meeting of YPF, an amendment to the By-laws was adopted to increase the number of Board members and permit the proportional representation on the Board of directors nominated by Repsol or Petersen SA, as the case may be (as indicated in the Schedule 13D).

(d) The description contained herein supplements Item 5 in the Schedule 13D and should be read in conjunction therewith.

As discussed in Item 3, Petersen SA assigned to Repsol its right to receive its share of the extraordinary dividend declared by the shareholders’ meeting of YPF on February 7, 2008, to be paid on or after February 29, 2008, pursuant to the terms of the Dividend Agreement. Such dividend was distributed on February 29, 2008, and paid to Repsol in the amount of Ps.630,574,801, which, pursuant to the currency conversion mechanism set forth in the Dividend Agreement (as described in the Schedule 13D), was equivalent to US$199,675,364 or US$1,474,636 less than the amount required to be paid under the SPA (i.e., US$201,150,000), and, therefore, in accordance with the terms of the Dividend Agreement, the outstanding principal amount under the Seller Credit Agreement will be increased by such difference.

The description contained herein supplements Item 6 in the Schedule 13D and should be read in conjunction therewith.

The information set forth under Items 3, 4, and 5 and in Exhibits 99.1 to 99.17 attached hereto is incorporated herein by reference.

To the knowledge of the Reporting Persons there are no other contracts, arrangements, understandings or relationships (legal or otherwise) among the Reporting Persons or between the Reporting Persons and any person with respect to any securities of the Issuer, including but not limited to transfer or voting of any of the securities of the Issuer, finder’s fees, joint ventures, loan or option arrangements, puts or calls, guarantees of profits, division of profits or loss, or the giving or withholding of proxies, or a pledge or contingency the occurrence of which would give another person voting power or investment power over the securities of the Issuer.

EXHIBIT INDEX

* Previously filed as an Exhibit to the Schedule 13D filed with the SEC on February 29, 2008.

SIGNATURE

After reasonable inquiry, and to the best of my knowledge and belief, I certify that the information set forth in this Statement is true, complete and correct.