The execution of European Union Law in member states

European Union created a dynamic legal system in the process of economic and political integration. Effective and uniform application of Union law is required in the European Union whose main objective is integration. Turkey is not a member of European Union. However, Turkey has relations with the Union for a long time. Since 03 October 2005 Turkey has been a country in the state of negotiation process. Considering the relations between Turkey and the Union, execution of Union law in member states is not important only for a potential membership, but also for contemporary relations.Our study consists of three chapters. In the first chapter of our study, fundamental characteristics of international law are specified and distinctions between International law and European Union law are analyzed.In chapter two, the relation between European Union law and national laws are analyzed. First of all, concepts like member state, nationality, European citizenship are explained in this analysis. In the second title of this chapter, the economic and political integration models are examined. In the third title of this chapter, powers of Union and member states are mentioned and the ways to use these powers are specified. Then the ECJ?s approach to principles of primacy, direct applicability and direct effect are mentioned. Member states? approaches to these principles are evaluated by giving examples of their regulations and practices.Finally, review process concerning the execution of Union law is analyzed in chapter three. Reviews realized at the Member states? level and reviews carried out at the European Union level for ensuring effective and uniform application are included in this analysis.Keywords: European Union, European Union Law, International Law, National Law, Integration.