Migration within Europe is an continuing social phenomenon of large scale, which affects the health of the individual migrants and also that of the populations.15 Although Austria cannot be considered as a typical country of immigration, such as the USA or Canada, since the 1960s, thousands of people have migrated to Austria.16 The vast majority of these immigrants came from Turkey and former Yugoslavia. Up to now, migrants are a minority, often with a lower social status than the host population.16 This low socio-economic position and minority status are frequently associated with increased chronic distress, a higher morbidity and an increased mortality rate.11,17,18 As special health problem of migrants, a high prevalence rate of overweight and obesity, especially among women and children or adolescents, was documented.11,16,19 Although overweight and obesity are becoming increasingly prevalent nearly all over the industrialised world at the beginning of the third millenium,20 to be migrant seems to represent a special risk factor for developing overweight or obesity, especially during childhood and adolescence.11,21–24 In Central and Northern Europe, a high prevalence of childhood and adolescence obesity was mainly found among migrants originating from Mediterranean countries, such as Italy, Turkey or Morocco.11,22,24 The results of the present study corroborate these observations: the percentages of overweight and/or obesity were significantly higher among migrant girls at all age groups. Especially girls from former Yugoslavia showed a high prevalence of overweight. At the age of 10 years, nearly 35% of the Yugoslavian girls were classified as overweight or obese. Although the percentage of overweight or obese Austrian girls was also extraordinary high ranging from 20% at the age of 6 up to 25% at the age of 10 years, the prevalence of overweight and obesity was markedly higher among the migrant group. Instead of ethnicity-associated differences in social status, no marked differences in the socio-economic situation was observable between the three ethnic groups considered in the present study. The educational level of children and their parents was rather low. The great majority of parents were classified as unskilled workers and more than 15% of the fathers were unemployed and depended on governmental assistance. No significant differences in paternal educational level and employment status was documented between the three ethnic groups. Therefore, socio-economic factors cannot be assumed to be responsible for these differences between the ethnic groups because all children belonged to the lower socio-economic stratum of Vienna. Within the present sample, household size, parental educational level and paternal employment status had no impact on weight status. This may be explained by the fact that socio-economic differences within the whole sample were minimal. Recently, a low social or socio-economic status are declared to be among the major risk factors for developing overweight during childhood.10,25 Ethnicity seems to be an independent risk factor for developing overweight because cultural factors seems to play an important role in its aetiology. Nutritional habits and activity patterns are highly influenced by culture and religious components.23,26–28 High-energy diet on the one hand and reduced physical activity characterised by long-time watching of TV29 on the other hand seemed to be the main reason for the high levels of overweight and obesity among migrant children observed in several European countries.11,22,24 The especially high levels of overweight and obesity among migrant girls documented in the present study are in accordance with the observations described in the studies above. Obesity among adolescent girls has also a profound impact on gynaecological health and fertility.30,31 Obesity and especially increased abdominal body fat are frequently associated with infertility, hyperandrogenism, menstrual disorders and ovulatory dysfunction.32 Especially the polycystic ovary syndrome (PCOS), the most frequent endocrine cause of infertility, is found predominantly among overweight females, even during adolescence.33,34 Therefore, overweight during adolescence is also discussed as one important cause for ovulatory dysfunction and infertility during adolescence and adulthood.35 On the other hand, childhood obesity often predicts obesity during adulthood. In the present sample, overweight or obesity at the age of 69 years increased the risk to remain overweight or obese during adolescence. This was especially true for migrant girls. During adulthood, obesity is an important risk factor during pregnancy and birth.36,37 It is well documented that maternal obesity is associated with higher rates of maternal complications, pre-eclampsia, caesarean delivery and neonatal complications because obese women suffer higher rates of type II diabetes and gestational diabetes and tend to deliver macrosome offspring.38 These obesity-associated fertility disorders and pregnancy complications may lead to various psychosocial problems especially for migrant women from Islamic societies such as Turkey. The social pressure to have children shortly after marriage is high, even among migrants in Austria.39 Involuntary childlessness leads to psychic disturbances, negative self-perception and various psychosomatic problems. Being a mother is essential for the female sex role and childlessness is regarded a disgrace.39 In case of PCOS, a weight reduction of at least 10% can improve the hormonal profile and clinical manifestations of PCOS; however, weight loss is difficult to achieve and even more difficult to maintain, especially among migrant girls and women. Postmenarcheal migrant girls often underlie strict cultural and religious pressures, characterised by extremely low physical activity outside the household. Ethnicity has a profound impact on weight status development between the age of 6 and 15 years. While only 64.8% of the overweight Austrian girls remain overweight until the age of 15 years, this was true for 72.0% of the Turkish girls and for 78.3% of the Yugoslavian girls. One special problem is the fact that neither the migrant children and adolescents by themselves nor their parents are worried about their high weight status. This may be due to the fact that up to now, overweight in Turkey or former Yugoslavia is a phenomenon predominantly found in social middle and high-income class.40 This leads to a culturally positive interpretation of overweight, which is not seen as an important long-time health risk. Overweight and obesity are therefore not only medical problemsbut are also biosocial and cultural problems. In the future, health professional should consider these biosocial and cultural factors in their concepts and prevention should start as early as possible41 because overweight seems to persist from childhood up to adolescence.