In Germany, and particularly in Berlin, the fall of the Wall in 1989 and the years following reunification were accompanied by a large influx of immigrants. These 'new' migrants in Berlin are added to the long-resident guestworker population in the western part of the city. This paper investigates the housing situation of the increasing population of foreigners before and after unification as well as the changing segregation of ethnic minorities. After a comparison of the different housing systems in East and West Berlin and their consequences for ethnic segregation in the 1980s, the main elements of the housing transformation since 1990 are identified and related to the changing residential patterns of foreigners. The patterns of four selected nationalities with divergent migration motives are analysed in more detail. The paper draws attention to differences between East and West Berlin as well as to recent convergences between the two parts of the city.