Hirsutism in women is frequently associated with increased levels of androgens. Studies of biochemical changes, however, have yielded conflicting results. This study compares the findings in 30 hirsute women with normal menses and those of 30 hirsute women with abnormal cycles. Of the women with abnormal menstruation, 73% had oligoamenorrhea only and the others had dysfunctional uterine bleeding. The abnormally menstruating group had a similar mean age but tended to have heavier body weights than those with normal cycles. Free and total testosterone levels were significantly higher in the abnormal group (total testosterone, 54 +/- 35 ng/dl vs 35 +/- 12 ng/dl, p = 0.004; free testosterone, 7.8 +/- 4.9 pg/ml vs 4.2 +/- 1.4 pg/ml, p = 0.002). The abnormal group tended to have higher levels of androstenedione than the normal group (227 +/- 116 ng/dl vs 139 +/- 59 ng/dl) but dehydroepiandrosterone sulfate (DHEAS) levels were similar (320 +/- 142 mg/dl vs 298 +/- 169 pg/dl). Levels of thyroxin, thyrotropin, and prolactin were comparable in the two groups. Among hirsute women those with abnormal menses tended to be heavier and to have higher levels of total testosterone, free testosterone, and androstenedione. This is consistent with the clinical impression, not previously documented, that of hirsute women, those with abnormal menses have more severe endocrine abnormalities than those with normal cycles.