Exhibit 15.1

KPMG KPMG Auditores Independentes

Av. Almirante Barroso, 52 — 4°
20031-000 — Rio de Janeiro, RJ — Brasil
Caixa Postal 2888
20001-970 — Rio de Janeiro, RJ — Brasil Central Tel 55 (21) 2515-9400
Fax 55 (21) 3515-9000
Internet www.kpmg.com.br

To
Petróleo Brasileiro S.A.—Petrobras
Rio de Janeiro, Brazil

January 18, 2010

With respect to the registration statement on Form F-3 (333-163665), we acknowledge our awareness of the incorporation by reference therein of our report dated November 23, 2010, related to our review of interim financial information of Petróleo Brasileiro S.A.—Petrobras.

Pursuant to Rule 436 under the Securities Act of 1933 (the “Act”), such report is not considered part of a registration statement prepared or certified by an independent registered public accounting firm, or a report prepared or certified by an independent registered public accounting firm within the meaning of Sections 7 and 11 of the Act.

/s/ KPMG Auditores Independentes  

KPMG Auditores Independentes 

Rio de Janeiro, Brazil