This paper deals with the main institutions of the European Union - the main governing bodies of the EU: the European Commission, the European Parliament, the European Council, the Council of the EU and the European Court of Justice. The term "institutions" refers to the governing bodies of the organization, which are entrusted with the implementation of its main tasks. The first chapter deals with their organizational structure and main functions. The European Union's system of institutions can be considered unique. In general, the main bodies of the European Union form the so-called "power triangle" represented by the European Commission, the Council of Ministers and the European Parliament. Therefore, special attention was paid to these very institutions. The second chapter deals with the main existing problems and processes in the European Union - the problem of ratification of the single European Constitution, its advantages and disadvantages, problems of reforms and institutional development of the EU. On the basis of this and the third chapter the existing drawbacks of the institutional structure of the EU are analyzed and possible ways of its improvement are suggested.This paper deals with the main institutions of the European Union - the main governing bodies of the EU: European Commission, European Parliament, European Council, Council of the EU and European Court of Justice.