The RIMED project deals with three serious and interacting problems of South-Eastern Europe: increasing spatial inequality, serious geographical and economic fragmentation and unbalanced or even anarchic growth of metropolitan areas leading to a further concentration of activities. The latter may lead to traffic congestion, pollution, environmental degradation and social segregation, which threaten to undermine the prospects of large cities for sustainable development. RIMED proposes a development strategy for South-Eastern Europe which is based on transnational networks of co-operation and which promotes polycentric urban development with widespread effects to the hinterlands of the large cities. The project is based on a network of co-operation among four important cities in the region, Sofia, Skopje, Tirana and Thessaloniki, and involves the administrative as well as scientific institutions from these cities. Achievements: This project managed to improve co-operation and to establish networks of interaction among major cities in South-Eastern Europe. In that sense it contributed to the general goals of the EU and international community in promoting stability, integration and co-operation in the region. In addition, the project contributed to a balanced and polycentric spatial development in the wider context of South-Eastern European space by supporting selected cities with a joint strategy of metropolitan development, which has a strong preference for regional cohesion and spread effects to metropolitan hinterlands. Other important effects include the improvement of local governance through a network-based transfer of know-how and experience.