The CENTURIO programme, created by the Assembly of European Regions (AER) in 1994, has been successfully promoting dialogue and exchange of experience between European regions for several years. However, the enlargement of the EU in May 2004 served to illustrate that the European and global context for the regions is changing. Their growth and competitiveness depend on their capacity to develop in a sustainable way. Europe’s regions are facing major challenges and it is in response to this that CENTURIO is enlarging its networks of cooperation and intensifying its activities. CENTURIO is helping Europe’s regions to achieve sustainable development in a rapidly changing European and global context. Its key objectives are to promote the improvement of regions’ policies and instruments for regional development and cohesion; to contribute to assessing the effectiveness and impact of the EU’s regional policy; to support the implementation of the EU’s regional policy in an enlarged EU; and to support regions from new and future member states as they adapt to the demands of EU membership.