Under the programme of payments for environmental services (PES) programme, economic recognition of forests moved from a ‘timber-only’ approach to a wider concept of ecosystem services that feeds directly into human and industrial functions of production or consumption. But who really benefits and loses from PES? A clearer understanding of distributional issues in PES-type projects is becoming increasingly important for the design of large-scale projects such as REDD+. This study looks in detail at the social impacts of the pioneering PES programme in Costa Rica, and addresses issues related to equity and poverty on the basis of long-term data from all the PES contracts signed. (the report in Spanish is also available at the website)