Since the 1990s, the member states of the European Union (EU) have in an increasing number of cases agreed to pool their individual market power in order to valorize their bargaining position in various global governance arrangements. The most prominent examples of those interactions with multilateral regimes certainly are the World Trade Organization and the global climate regime. Against this background, this paper has a theoretical and an empirical aim. Concerning the theoretical perspective, the paper proposes an extended multi-level governance approach (eMLG) in order to analyze the dynamics of institutional change that emerge both at the EU and the member states’ level as a consequence of the agreement to Europeanize the mediation of national interests. Empirically, I refer to the example of global pharmaceutical regulation and I ask why even larger member states of the EU, such as Germany, engage in the Europeanization of interest mediation and under what conditions they are able to pursue their interests if the European Commission represents them at the global stage. In this respect I argue that not the size or the relative power of individual member states play a decisive role, but their ability to make use of the institutional multi-level structure.