In recent years, indirect land use changes (ILUC) have benn discussed intensely and controversially both in the scientific and in the political sphere. Since 2009, they have become one of the central conflicts within the european biofuels policy. This conflict is characterized by the production of scientific knowledge on ILUC and its significance in the political process. Based on this finding, it is the aim of this article to take a closer look at the processes of problem definition, the design of the ‘science-policy interface ' and the ensuing political repercussions. The article asks how the dispute over the scientific evidence and quantification of ILUC could play such a central role in the policy process, how this influenced in policy formulation at the EU level, and what consequences this way of dealing with scientific evidence has for the policy process.