Obesity has been reported in developed as well as developing countries. However, data on a large sample of the Indian population are lacking. This study analysed the prevalence of obesity among 1,784 adults in Bombay from various sections of society. Since the prevalence of obesity depends upon the criteria used, prevalence was judged by three criteria viz. percentage excess of body weight, body mass index, and body fat content. The data were classified and analysed according to occupation, age group, income, diet type, and also with respect to family history of obesity. The three methods gave a different prevalence of obesity. In general, the criterion of body mass index under-estimated, and body fat content over-estimated the prevalence as compared to that obtained by percentage excess body weight. An extremely high prevalence of obesity was found in all sub-groups of the sample. As judged by a body mass index of 25 and above, male students had the lowest (10.7%) and male medical doctors had the highest (53.1%) prevalence of obesity. Prevalence was highest for the age group 31-50 years for males and females, and declined on either side of this age range. Prevalence was directly proportional to financial income, and subjects with a family history of obesity had a greater prevalence of obesity compared to those without. This study indicates the gravity of the problem of obesity in Bombay, and provides directions for nutritional planning in the future.