INTRODUCTION: The purpose of this study was to describe the prevalence of overweight and variations in physical activity and smoking habits among parents in three suburbs of Copenhagen, focusing on differences related to ethnic Danish and bilingual children, respectively. MATERIAL AND METHODS: The health profile was completed as part of a physician health check-up at school start. The questionnaire included registration of the parents' employment status, parental smoking habits, and health behaviour among the children. The children's height and weight were registered. A total of 823 children were included (participation rate of 96.1%) of which 201 were bilingual. RESULTS: 21.2% of the children had a weight exceeding the 90 percentile (based on a Danish standard). Of these, 8.7% had a weight exceeding the 97 percentile. 32.2% of the bilingual children were overweight while 18% of the ethnic Danish children were overweight (p = 0.001). Fewer children were overweight in the more affluent suburb to the north of Copenhagen than in the two other suburbs. Fewer bilingual children were involved in organized sports and walked or cycled to school. More bilingual children were exposed to passive smoking in the home and spent longer time in front of a screen. CONCLUSION: At school start, approximately one fifth of the children in three Copenhagen suburbs had a weight exceeding the 90 percentile and approximately 9% over the 97 percentile. Bilingual children were more often exposed to risk factors predisposing to lifestyle diseases.