The prevalence of diabetes mellitus (DM) and cardiovascular disease (CVD) is increasing in urban India. Overweight in adolescence is a marker of overweight in adult age, and it shows an association with the above diseases. There have been meagre data from India on the prevalence of childhood obesity. The objective of the study was to quantify the prevalence of overweight and its risk factors in adolescent children in urban India. School students in the age group of 13-18 years (n = 4700, M:F 2382:2318) were studied. Body mass index (BMI) was measured. Data on physical activity, food habits, occupation of parents and their economic status, birth weight of the children and age at menarche in girls were obtained by questionnaire. Age-adjusted prevalence of overweight was 17.8% for boys and 15.8% for girls. It increased with age and was higher in lower tertiles of physical activity and in higher socio-economic group. Birth weight and current BMI were positively associated. The study highlighted the high prevalence of overweight in adolescent children in urban India. Life style factors influenced BMI in adolescent age.