||The European Neighbourhood Policy was launched in the year 2004 and aimed at promoting prosperity, stability and security in the neighbouring countries. The Thesis tests the explanatory power of European Integration theories in explaining the formation of the European Neighbourhood Policy on the European level. Elements of the theory of Liberal Intergovernmentalism, the theory of intensive transgovernmentalism and historical institutionalism are used. The Thesis aims to answer the question why the European Neighbourhood Policy appeared on the ENP, which factors influenced its shape and who were the relevant actors. The ENP is an interesting policy to research for different reasons. The countries participating in the ENP differ in their political and economic development. Furthermore, after the Enlargement round in 2004 it was one of the first foreign policies in which the European Commission had a significant role. The Thesis aims to analyse the interplay between the European Institutions which led to the current policy and the policy emphasis on security and stability. The relevant documents of the European Commission, the Presidency Conclusions of the European Council and the Conclusions of the General Affairs and External Relations Council were analysed. The Enlargement of the EU in 2004 triggered the initiation of the ENP as it led to a new neighbourhood of the EU, this can be explained by the mechanism of Path-dependency. The preferences of the Member States of the EU, the decision to conduct in common the relations with the new neighbourhood on a European level and the economic cooperation with the new neighbouring states can be explained with the Liberal Intergovernmentalism. The intensive transgovernmentalism explains the distinguished role of few Member States in initiating the ENP, for example as Poland. It is assumed that the European Council and the General Affairs and External Relations Council set the objectives as prosperity, stability and security on the basis of the Member States preferences. The Commission used similar tools as in the policy of Enlargement, for example conditionality, and expanded its influence in the policy of foreign affairs. Its influence on the objectives was limited.