Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F. 

Form 20-F ___X___ Form 40-F _______

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____

Declaration of Commercial Potential of New Giant Field in the Campos Basin

Preliminary appraisals point out that the new field, located in the evaluation plan of the former BC-20 block, at South of Campos Basin, is a giant field, with potential recoverable oil volumes between 700 million and 1 billion barrels of oil equivalent. The well 4-BRSA-2180-RJS is located in a water depth of 1,200 meters, showing crude oil with an API between 14º and 17º. The preliminary delimitation of the new field, discovered in 2003, resulted of the drill of five wells, beyond the pioneer and also an acquisition of 30 thousand kilometers of seismic lines.

This is an area operated by Petrobras, with working interest of 62.5% of the concession acquired in consortium with Chevron Overseas of Brazil Ltda in 1998, which participates with 37.5% of the investments.

The expectation of the Petrobras is that the new field can start production at the end of 2011, giving an important contribution for the Brazilian production of oil and gas.

This document may contain forecasts that merely reflect the expectations of the Company’s management. Such terms as “anticipate”, “believe”, “expect”, “forecast”, “intend”, “plan”, “project”, “seek”, “should”, along with similar or analogous expressions, are used to identify such forecasts. These predictions evidently involve risks and uncertainties, whether foreseen or not by the Company. Therefore, the future results of operations may differ from current expectations, and readers must not base their expectations exclusively on the information presented herein.

This press release may contain forward-looking statements. These statements are statements that are not historical facts, and are based on management's current view and estimates offuture economic circumstances, industry conditions, company performance and financial results. The words "anticipates", "believes", "estimates", "expects", "plans" and similar expressions, as they relate to the company, are intended to identify forward-looking statements. Statements regarding the declaration or payment of dividends, the implementation of principal operating and financing strategies and capital expenditure plans, the direction of future operations and the factors or trends affecting financial condition, liquidity or results of operations are examples of forward-looking statements. Such statements reflect the current views of management and are subject to a number of risks and uncertainties. There is no guarantee that the expected events, trends or results will actually occur. The statements are based on many assumptions and factors, including general economic and market conditions, industry conditions, and operating factors. Any changes in such assumptions or factors could cause actual results to differ materially from current expectations.