OBJECTIVE: Comparative data on ecological differences in body fatness and fat distribution within Europe are sparse. Migration studies may provide information on the impact of environmental factors on body size in different populations. The objective was to investigate differences in adiposity between European immigrants and native Swedes, specifically to examine gender differences and the effect of time since immigration, and to compare two selected immigrant groups with their native countrymen. RESEARCH METHODS AND PROCEDURES: A cross-sectional analysis of 27,808 adults aged 45 to 73 years participating in the Malmö Diet and Cancer prospective cohort study in Sweden was performed. Percentage body fat (impedance analysis) and waist-hip ratio (WHR) were compared between Swedish-born and foreign-born participants. RESULTS: Obesity was 40% more prevalent in non-Swedish Europeans compared with Swedes. Controlling for age, height, smoking, physical activity, and occupation, it was found that women born in the former Yugoslavia, southern Europe, Hungary, and Finland had a significantly higher percentage of body fat, and those from Hungary, Poland, and Germany had more centralized adiposity compared with Swedish women. Men born in the former Yugoslavia, Hungary, and Denmark had a significantly higher mean percentage of body fat compared with Swedish-born men, whereas Yugoslavian, Finnish, and German men differed significantly in mean WHR. Length of residence in Sweden was inversely associated with central adiposity in immigrants. A comparison between German and Danish immigrants, their respective native populations, and Swedes indicated an intermediate positioning of German immigrants with regard to body mass index and WHR. DISCUSSION: Differences in general and central adiposity by country of origin appear to remain after migration. Central adiposity seems to be more influenced than fatness per se by time of residency in Sweden.