EXHIBIT 15.1 (ERNST & YOUNG LOGO) o Praia de Botafogo, o Fone: (55)(21)2109-1400 300 - 13(degree) andar Fax: (55)(21)2109-1600 22250-040 - Rio de Janeiro, www.ey.com.br RJ, Brasil December 15, 2006 SHAREHOLDERS AND BOARD OF DIRECTORS Petroleo Brasileiro S.A.-Petrobras We are aware of the incorporation by reference in this Registration Statements (Form F-3 No. 333-) and in the accompanying prospectus supplement of Petroleo Brasileiro S.A. - PETROBRAS ("Petrobras") and Petrobras International Finance Company ("PIFCo") of our reports dated November 11, 2005 relating to the unaudited condensed consolidated interim financial statements of Petrobras and of PIFCo for the nine months ended September 30, 2005 included in the Forms 6-K dated November 23, 2005 and November 29, 2005, respectively. Very truly yours, ERNST & YOUNG Auditores Independentes S.S. /s/ Paulo Jose Machado Paulo Jose Machado Partner