One of the most urgent problems of East German Cities at present time is the huge amount of unoccupied apartments. In contrast with many other East and Central European countries, housing shortage is not on the agenda. It is estimated that more than one million apartments (13% of the whole housing stock) are empty. Already in 1990, about 400,000 dwellings were unoccupied because of a bad state of repair caused by a longterm neglect of the older tenemental areas by the former state. At present, there are serious prognoses until 2030, announcing an amount of vacant apartments of 1,5 to 2 million, if there will be no strategies acting against. What are the explanations of this unusual situation, what are the consequences for urban life and reside, and how can the cities deal with such a new phenomenon? These questions are in the focus of an ongoing research project, carried out in a co-operation between sociologists, economists, ecologists and jurists.