Polycystic ovary syndrome (PCOS) is the most common endocrine and metabolic disorder affecting women in reproductive age. Although the etiology of PCOS remains unclear, it is believed to result from genetic, environmental and behavioral interactions. Women with PCOS have higher lifetime risk for cardiovascular disease (CVR) than healthy women at the same age and tend to display insulin resistance (IR). IR has traditionally been defined as a decreased ability of insulin to mediate the metabolic actions on glucose uptake, glucose production, and/or lipolysis. This results in a requirement for increased amounts of insulin to achieve a given metabolic action. Metabolic syndrome (MS) includes hyperinsulinemia, dyslipidemia, increased CVR and hyperleptinemia and metabolic disorders such as hypertension, IR, gestational diabetes, type 2 diabetes mellitus, systemic inflammation and endothelial dysfunction. The prevalence of MS in women is around 50 %. In addition, it has been recently suggested that women with MS show increased circulating androgens. The present review discusses the main alterations and features of PCOS and MS and the most important treatments.