Because insulin resistance and visceral obesity are important features of polycystic ovary syndrome (PCOS), metabolic syndrome is much more common in women with PCOS than in the general female population of similar age. It has been reported that in the USA almost 50% of women with PCOS present the metabolic syndrome. In Italy, where women with PCOS have a lower mean body weight and less frequently increased serum triglycerides than US PCOS, metabolic syndrome is less common but still 4 times more frequent in PCOS patients than in the general female population of similar age. Patients with mild PCOS phenotype (ovulatory PCOS) have a lower prevalence of metabolic syndrome but, in these patients too, metabolic syndrome is 2 times more frequent than in the normal population. These data suggest that PCOS is the most common cause of increased cardiovascular risk in young adult women. All obese and overweight women with PCOS should be screened for metabolic syndrome and, when the syndrome is not found, the screening should be repeated every 2 or 3 years. Treatment consists in lifestyle intervention. Pharmacological therapies should be used only when lifestyle fails to normalize cardiovascular risk factors.