Many prominent sectors of the international agricultural commodities market have been calling upon their stakeholders to define and implement social responsibility and sustainability benchmarks, aiming at product quality and production practices certification. One of these initiatives, the Roundtable for Sustainable Palm Oil (RSPO), is compelling all producing parties (plantations as well as smallholders) to comply with proposed Principles, Criteria and Indicators (PC&I), in an international social responsibility assurance movement. In addition to these PC&I, an integrated sustainability assessment procedure is being sought out in a Cirad / Embrapa / Partners coordinated effort, as a complementary method for the environmental management of oil palm plantations. The aim is to assure both procedural social responsibility (PC&I compliance) and actual environmental and biodiversity conservation in the field. The proposed action to fulfill this objective has been the adaptation of a 'System for Weighted Environmental Impact Assessment in Oil Palm Production' (APOIA-OilPalm). The present document reports on the conceptual basis, the methodological adaptation and the validation field trials carried out for consolidation of the proposed APOIA-OilPalm sustainability index. The experience attained in the development and international negotiation of this proposed sustainability index, dedicated to such an important productive sector such as that of palm oil, can be instrumental for other environmental management and eco-certification initiatives, such as the Roundtables on Responsible Soy, Sustainable Biofuels, and Sustainable Forests; the Better Sugarcane Initiative, among others.