The focus of this article is to find out how governance functions in an expanded multi-level system. The aim is to analyse institutional change within the EU which is caused by the EU's international embeddedness. The paper develops and empirically tests the hypothesis that embeddedness of the EU within an international context does not only affect the formal organization of the European decision- making process. It includes effects on routines, guiding ideas and concepts of legitimate order as well. The World Trade Organization (WTO) serves as a case to analyse these effects. The empirical research covers the overall European institutional changes within the different issue-areas of WTO (GATT, TRIPS and GATS), including its dispute settlement system, as well as the discussion about the involvement of civil society in the WTO's decision-making and its effects on the EU.