OBJECTIVE: To determine the prevalence of polycystic ovary syndrome (PCOS) among hyperandrogenic women who report normal menses. DESIGN: Prospective observational study. SETTING: Academic practice in reproductive endocrinology. PATIENT(S): Fifty-eight consecutively seen new patients with hyperandrogenism who reported normal menses. INTERVENTION(S): Ovulatory status was assessed with timed serum progesterone measurements. The following tests also were carried out: vaginal ultrasound examination; measurement of the ovarian response of 17-hydroxyprogesterone (17-OHP) after the administration of leuprolide acetate, 1 mg SC; and determination of fasting serum LH, FSH, E2, 17-OHP, insulin, and androgen levels. MAIN OUTCOME MEASURE(S): Determination of ovulatory status, polycystic appearance of ovaries, and increased response of 17-OHP to leuprolide acetate. RESULT(S): Twelve (20.7%) of the hyperandrogenic women were anovulatory and met the usual criteria for the diagnosis of PCOS. The ovulatory patients had lower serum total and unbound testosterone levels. Thirty-one (53.4%) of the ovulatory women had polycystic ovaries on ultrasound examination and/or an increased 17-OHP response to leuprolide acetate, suggesting the diagnosis of PCOS despite the presence of ovulation. Considering both the anovulatory and ovulatory patients, 74% of the hyperandrogenic women studied could have PCOS. CONCLUSION(S): The data suggest that most (74%) hyperandrogenic women who report normal menses have evidence for the diagnosis of PCOS.