Each enlargement of the European Communities (EC) and later the European Union (EU) has had an indisputable in! uence on inner cohesion of the organization itself. The participants of the integration processes have included the countries deviating from the previous Member States by the level of the economic development, the structures of their economies, macroeconomic conditions, etc. This differentiation has taken its toll especially on the functioning and the expenses of common policies (mainly transfer ones) as well as the execution of the integration reinforcement plans such as the European Economic and Monetary Union. In this aspect the most serious consequences were caused by the admission of countries that were much weaker economically, especially Ireland, Greece, Spain and Portugal. These countries had to go through a long way of reforms in order to become rightful members of the organization and for their integration with the Communities to become a mutual success. A big part of the expenses connected with these reforms was financed by the common budget thanks to the structural funds and the Common Agricultural Policy.