development within the EU. In the introductory chapter on regional development in the EU, the concept of the region and the role of regional development in the EU are highlighted. Subsequently and in preparation for the main chapter, the regional policy relevant basics of the EU are explained, as well as the European Regional Development Fund, as it finances the Interreg programme. The main part of the work is devoted to the Interreg Programme: First of all, the organisation, financing and objectives of the programme are examined, followed by the development and history of Interreg. Finally, an example of cross-border cooperation, within the framework of Interreg, namely between Germany and Denmark, and an example project "Undine II" which is part of the cooperation.