Öz The tasks and responsibilities of the institutions, which are specified by the EU treaties, have been subject to scholarly debate. With the changes that are occurring in the EU political system, an emphasis is placed on the question of how much the principle of subsidiarity can advance the practice of integration in terms of the decision-making capacity of the institutions. A particular attention is paid to the question of whether principle can have major positive effects by helping to shape the institutions within which democracy can operate. This paper explores the possible impact of the principle on the EU institutions.