Regional policy is one of the most important policies of the European Union, it fosters competitiveness, economic growth and development, takes care of job creation and improves quality of life. As there are major differences in the progress of individual regions and member states of the European Union, its main objective is to reduce development gaps between member states' regions. Under regional policy, the EU operates the European Structural and Investment Funds, which are the main instrument for applying European policies. In order to foster the economic development of less developed areas, regional aid is granted and the basic precondition for granting them is the existence of a regional aid map. A new map of regional aid suggests 4 NUTS2 regions that were created by grouping counties as administrative units. Regional development policy is monitored and evaluated in order to increase efficiency and impact on regional development, it contributes to the balanced and harmonious development of the Republic of Croatia and ensures the preservation and protection of the environment and cultural wealth and is implemented in accordance with the autonomy of regional selfgovernment units and is guaranteed by the Constitution of the Republic of Croatia. The graduate thesis will explain the history of the European Union, the beginnings and development, the principles, regional policy financial instruments and regional structural and investment funds. The Regional Policy of the Republic of Croatia, NUTS classification, principles and holders of regional policy of the Republic of Croatia will be explained, and at the very end of the work will be given successful examples of EU funds in the area of BrodskoPosavina County.