One of the first structures of the international environmental governance architecture ever to be created, the Global Environment Facility (GEF) is still today the only international tool with the protection of the global environment as its primary mandate. It faces at present a series of challenges today, the most prominent being the transformation of the international environmental governance landscape, intensified by the rise in importance of the issue of global climate change on the agendas of states. On the basis of interviews carried out in Washington, New York, Geneva and Paris, 'The Global Environment Facility: Managing the Transition' analyses the challenges faced by the GEF and outlines some recommendations in this regard.