Objective To study the effects of increasingly prosperous diet content on clinical features of polycystic ovary syndrome (PCOS). Design A cross-sectional cohort study of 711 women with PCOS from a heterogeneous population spanning a wide spectrum of socioeconomic strata. Setting Independent hospital. Patient(s) A total of 711 women with PCOS in whom the diagnosis was based on Rotterdam criteria. Results were compared with a locally recruited reference group. Intervention(s) Clinical assessment of women with PCOS. Main Outcome Measure(s) Clinical characteristics were assessed with particular reference to diet composition. Four diet groups were identified: simple rice with vegetables, vegetarian with mixed carbohydrates, nonvegetarian with mixed carbohydrates, and an urban diet of processed foods. Result(s) Women with PCOS showed the characteristic features of raised LH and androstenedione concentrations and increased ovarian volume and antral follicle count. There was a notable association between an increasingly affluent diet, the presence of hirsutism, raised body mass index, insulin resistance, and higher serum antimullerian hormone concentrations. The positive association between antimullerian hormone and body mass index is an unusual feature possibly explained by the wide spectrum of lifestyles in this cohort. Conclusion(s) Urbanization of women in India is associated with increasingly severe phenotype of PCOS, which is likely to have implications on fertility outcomes.