The intention of this master thesis was to complete my studies in urban and regional planning (Raumplanung) at the Vienna University of Technology. It contains a discussion of new challenges and problems occurring to cities and city-regions in a global competition and therefore strengthen the need for co-operation dealing with new geopolitical situations. Further on, an analysis of different forms of co-operation in cross-border city-regions, by way of two case studies, namely the Copenhagen-Malmö region and the Vienna-Bratislava region was done. These two case studies were chosen because of their geographic and historic situation. The cases were analysed in their performance regarding the progress of cross-border integration and their co-operation status.