This article discusses factors effecting the implementation of European policies at the national level. Four main independent variables are distinguished: political institutions, the degree of corporatism, citizens' support for the EU, and political culture in the member states. The impacts of these variables on the success of implementing EU directives in ten policy areas are then tested with the multiple regression model. The results suggest that political culture and the design of political institutions in the member states had the most significant impact on implementation behavior. Countries with a high level of trust and political stability combined with efficient and flexible political institutions had the most success in implementing European policies.