Ethnic segregation is consolidated by differences between ethnic groups with regard to their moving decision. Using unique registration data on population flows between neighbourhoods we show that native Dutch living in neighbourhoods where ethnic minorities are overrepresented are more likely to move than minority ethnic residents. Moreover, they move much more often to ‘white’ neighbourhoods. Urban policies in the Netherlands focus on countering this tendency of segregation, but are based on simplified assumptions with regard to the causes of residential segregation. Next to that, the optimism about the positive effects of social mix is hardly substantiated by empirical research.