The European Union is the only economic union that exists in the world. In this paper we analyze the historical evolution of the instauration of the European Union, furthermore we analyze the functioning of the European Union and its institutions with special emphasis on the institutions that affect the economic sphere and finally we analyze the achievements and difficulties encountered during the EU integration process. As a result, the study reveals that many are the economic, political and social achievements that the European Union has reach so far, however, there are difficulties that have become apparent because of the impact of the international financial crisis on the economies of Member States, for which is necessary the creation and / or strengthening of institutions and mechanisms that enable a mayor and better coordination of fiscal and monetary policies in order that consequences of eventual economic and financial shocks of a country member, does not shake the finance of the entire region.
