Since the 1980s, the European Union has created mechanisms to integrate the increasing lobbying activity of European-wide interest groups. This has led to considerable pressures upon national interest groups to participate in European level organisations. This chapter will focus on how Portuguese interest groups reacted to these Europeanisation pressures in the EU multi-level governance system. It is frequently argued that, due to common pressures such as economic and monetary union (EMU), Trade Unions and Business associations need to work together more closely at the European level. This chapter maintains that although Portuguese employers and Trade Union actors have gained some multi-level leverage after joining the major transnational Eurogroups, they still lag behind in terms of using all the possibilities of influence in the multilevel governance system. Their actions consist in reacting to policies set up by the Eurogroups in which they are integrated. The chapter explores how Europe impacts on the day-to-day business of these groups and will offer some explanations as to why they fail to exploit its full potential.