The phenomenon of the »shrinking city« is becoming ever more significant: a declining population and overaging characterize current demographic trends in Germany. Today's guiding urban development principles must be updated and revised. The City of Duisburg has undertaken the task of analyzing in an exemplary project those infrastructures which are influenced by demographic developments and cause expenditures, and to study the prospects for their financing in the future. AS+P was commissioned in March 2005 to draw up a comprehensive urban development concept which integrates in a representative manner sectoral infrastructure planning and sets the stage for the further development of Duisburg in the context of a shrinking city. Upon the basis of the analysis - in particular regarding the demand for residential areas, daycare centers, primary schools and senior citizen facilities and the aspect of sewage treatment facilities - it was possible to develop innovative proposals according to the motto »Shrinkage as a Chance«. A small but effective infrastructure bundle was compiled that satisfies the demands of a declining population while also offering the chance to create new urban qualities in Duisburg.