Recent diagnostic and pharmacologic developments have focused renewed attention on polycystic ovary syndrome. Clinical features of the syndrome include anovulation, hyperandrogenism and menstrual dysfunction, but several other abnormalities, including hyperinsulinemia, luteinizing hormone hypersecretion, elevated testosterone levels and acyclic estrogen production, have been documented. Accompanying obesity and lipid abnormalities compound the risk of developing diabetes mellitus or cardiovascular disease, and chronic anovulation increases the risk for endometrial cancer. A careful history and physical examination should guide diagnostic testing. Slowly progressive hyperandrogenic symptoms with anovulation of peripubertal onset often represent polycystic ovary syndrome. Treatment goals include symptom management and the identification and prevention of potential cardiovascular risks. Treatment should take into account the patient's desire for fertility. Advances in transvaginal ultrasonography and infertility treatments, including newer medications, have facilitated assisted reproduction in patients with polycystic ovary syndrome. Ongoing pharmacologic research focusing on the treatment of insulin resistance appears promising in reversing the longterm complications of the syndrome.