In Brazil, Offshore Oil & Gas Exploration and Production activities have to be submitted to an environmental permitting process. The Environmental Agency of Brazil - IBAMA - responsible for this process, adopted, in 2009, the Environmental Risk Analysis (ERA) in the studies that undertakes the license grant. In order to meet these new requirements, a multidisciplinary team composed by biologists, oceanographers, engineers as well as risk assessment, modeling and GIS experts have developed studies based on the interpretation of the IBAMA’s requests. The ERA methodology relies on three main steps: calculus of operational risk; results from numerical oil modeling; identification of Components with Environmental Value (CEV), with their Recovery Period and probability of particular CEV being reached by an oil volume range. By integrating these types of analyzes is possible to calculate the environmental risk for each volume range and each seasonal scenario. The joining of these areas provide the necessary information for the environmental risk assessment approach, which will lead to the tolerability index, that is the goal of the ERA study. Despite the uncertainties involved in this process, mainly in terms of previous information of these three areas (i. e. recovery period and baseline studies, specific failure rates data basis, etc.) which should be minimized by considering a better relationship between operators, consultants and public agencies to achieve results closer of the reality. Finally, the ERA consists of an innovative methodology for oil and gas permitting in Brazil. But more than a new methodology, it is a more comprehensive analysis and advanced tool to support the studies, since it integrates three important areas of the studies within a single indicator (tolerability index), which simplifies the process of assessing the viability and risks of a proposed offshore Oil & Gas project.