The clinical features of polycystic ovary syndrome (PCOS) include hirsutism and irregular menses, which are the results of ovarian hyperandrogenism and chronic, unopposed estrogen secretion. The discovery that most women with PCOS are insulin-resistant and have compensatory hyperinsulinemia, with increased risk for type 2 diabetes mellitus, designates this condition as a reproductive-metabolic disorder. That the symptoms of PCOS may be mimicked by other endocrine disorders of the ovary and adrenal glands warrants careful evaluation to exclude these associated conditions.