Biofuels as a renewable source of energy have gained considerable importance in recent years. The use of biofuels is expected to rise since national governments of developed nations like the US and European countries see it as one of the ways to fulfill climate targets and increase the security in their energy supply. Production of biofuels is also expected to rise as developing nations see in biofuels the opportunity for connecting to international markets through supplying a new demand in the energy market.Several studies report on the environmental, social and economic gains and detriments that can arise from increased biofuel production and consumption. However, research that provides insight into the way in which such issues are defined by actors within the product chain is scarce. In this article we analyse how the strategies and value definitions of actors involved in the production and consumption of biofuels lead to specific definitions of sustainability. The empirical material concerns the chain of palm oil production in Colombia and electricity generation in the Netherlands. It is analysed using the method of action-in-context, which allows us to uncover the level and source of diversity of sustainability definitions in the product chain.While the current growth in production of palm oil is definitely buyer driven, the analysis of various activities in the chain shows that several aspects of sustainability are defined in more complex actor fields throughout the product chain. (C) 2010 Elsevier Ltd. All rights reserved.