This thesis explores the involvement of the European Union (EU) in the international negotiations for the formation of a climate change regime. Following g a short introduction into the Union's origins, this piece of work traces the subsequent evolution of the latter's environmental policy and examines the Union as an actor in climate politics. Then, after briefly covering the scientific developments that led to the inclusion of climate change in the international political agenda in the late 1980s, the study attempts to cover in detail the period of formal climate negotiations (1988-2007), focusing on the role played in them by the European Union.