The creation of a competitive internal electricity market has been an important topic on the European agenda since 1988. However, after 20 years of efforts to achieve this objective, the Commission in 2008 acknowledged, that market integration in the energy sector still had not developed to a sufficient extent. This can be mainly attributed to the resistance of certain large public utility companies (in particular from France and Germany) which wanted to protect their existing domestic monopolies and thus tried to shield their home markets from competition. Given the ability of these stakeholders to obstruct the liberalisation and integration of one of Europe’s most important industrial sectors examining the mechanics of successful corporate influence on EU decision-making in the area of electricity policy becomes of significant importance for both economic and political science research. The paper therefore wants to answer the question of why large public utility companies opposed to domestic market opening were more successful in asserting their interests in European energy policy making than the proponents of liberalisation. In doing so it is the primary objective of the research to identify the factors that ac-count for the success of corporate influence on EU decision-making in the field of electricity legislation. The analyses therefore traces back specific policy outcomes of the latest legislative process (2007-2009) to the intervention of certain economic ac-tors and examines how and to what extent their individual capabilities, instruments and strategies of influence enabled those actors to have their interests recognised.