Abstract : The Roundtable on Sustainable Palm Oil (RSPO) is a non-profit association that was created in 2003 and legally registered in 2004. It promotes the production and consumption of sustainable palm oil through a voluntary certification scheme. This certification scheme was developed by the stakeholders of the seven sectors involved in the palm oil commodity chain: growers, processors/traders, social NGOs, environmental NGOs, manufacturers, retailers, and banks. It relies, for the growers, on the compliance with the principles and criteria (P&Cs) of sustainability that were defined by consensus in 2007. These 39 P&Cs cover 8 dimensions: 1) Commitment to transparency [2 criteria], 2) Compliance with applicable laws and regulations [3 criteria], 3) Commitment to long-term economic and financial viability [1 criterion], 4) Use of appropriate best practices by growers and millers [8 criteria], 5) Environmental responsibility and conservation of natural resources and biodiversity [6 criteria], 6) Responsible consideration for employees and for individuals and communities affected by growers and mills [11 criteria], 7) Responsible development of new plantings [7 criteria], and 8) Commitment to continuous improvement [1 criterion]. The certified unit is the mill with its supply base. For out-growers supplying the certified mill, such as smallholders, a three-year delay is given to account for their difficulties in implementing the P&Cs. Other stakeholders involved in the supply chain must also fulfill specific requirements to allow for the complete chain certification. According to the supply chain certification systems, the final product may be labeled with the "Certified Sustainable Palm Oil" (CSPO) logo in the case of "Identity Preserved" or "Segregation". Alternatively, CSPO may be used to show support to the production of RSPO-certified palm oil without physical traceability of the produced amounts in the cases of "Mass Balance" and "Book and Claim" schemes. Nowadays, palm oil is the most used vegetable oil worldwide, representing more than 30% of total produced vegetable oils (Omont, 2010). With its 570 ordinary members, including 98 growers and 207 processors and traders, RSPO assembles 40% of worldwide palm oil producers and 20% of buyers. Despite a rapid increase in its production in the last 3 years, RSPO-certified palm oil (CSPO + CSPKO) represents today between 10 and 15% of global production (USDA, 2011 and RSPO, 2011) with only 50% uptake by the market. RSPO is directed by an executive board (EB) of 16 seats convening the diverse stakeholders. The EB plays a major role in organizing the annual general assembly, the highest RSPO authority, approving certification bodies and supervising member groups such as the taskforce on national interpretation of the P&Cs and the taskforce on revising the P&Cs, which must be done every 5 years. The executive board has also commissioned a working group on greenhouse gas (GHG WG) with the aim of identifying ways leading to meaningful and verifiable reduction of GHG emissions. Two successive science-based GHG WG have been active between 2009-2011, focusing on the review and development of methodological approaches and data that are accurate and relevant for diverse palm oil production systems. Such robust data and approaches underpin the outcomes of the GHG WG. Activities during the last two years were i) to organise a common harmonized framework for GHG accounting, ii) to develop a plan for moving forward via voluntary action, iii) to coordinate work with the group on peat land, and iv) to identify opportunities to reduce GHG from land use change. At the end of its mandate (November 2011), the GHG WG provided the EB with recommendations regarding the consideration of greenhouse gases within P&Cs to be considered by the taskforce revising the P&Cs. These recommendations include the use of a tool such as PalmGHG (or equivalent) to calculate the greenhouse gas balances of oil palm products. PalmGHG was developed by the workstream 1 of the GHG WG. It is an excel spreadsheet using the life cycle assessment approach and based on a previous tool by Chase & Henson (2010). The greenhouse gas balances are calculated for one mill and its supply base, as for the certification scheme. It allows for the calculation of greenhouse gas balances for diverse products such as crude palm oil or palm biodiesel (according to 2009/28/EC), and for scenario testing. It must be still peer-reviewed and upgraded to a user-friendly software. Other recommendations of the GHG WG refer e.g. to the characteristics that should be met by new plantations in order to ensure low GHG emissions.