The rise in world oil prices, coupled with heightened interest in the abatement of greenhouse gas emissions, led to a sharp increase in biofuels production around the world. Previous authors have devoted considerable attention to the impacts of these policies on a country-by-country basis. However, there are also strong interactions among these programs, as they compete in world markets for feedstocks and ultimately for a limited supply of global land. In this paper we offer the first global assessment of biofuel programs-focusing particularly on the EU and US. We begin with an historical analysis of the period 2001-2006, which also permits us to validate the model. We then conduct an ex ante analysis of mandates in the year 2015. We find that if these mandates are indeed fulfilled the impact on global land use could be substantial, with potentially significant implications for greenhouse gas emissions.