The relative contributions of the ovary and the adrenal gland to androgen overproduction in polycystic ovarian disease (PCOD) remain controversial. In this investigation, patients with proven PCOD were divided into two groups, (1) those with low dehydroepiandrosterone sulfate (DHEAS) levels and (2) those with high DHEAS levels, and compared with controls for their response to adrenocorticotropin hormone (ACTH) stimulation. Significant differences in weight, degree of menstrual disturbance, and basal progesterone levels distinguished the two groups with PCOD. Although no discrete enzyme block was unmasked by ACTH, marked differences in steroid production ratios were apparent between the low and high DHEAS PCOD groups. These results suggest that in PCOD with high DHEAS (1) substantial differences in adrenal steroidogenesis pathways occur, (2) increased progesterone as well as inappropriate estrogen feedback may contribute to chronic anovulation, and (3) serum DHEAS levels may be a helpful screen in discerning those patients who have a significant adrenal component to their hyperandrogenism and may benefit from adrenal suppression alone or in combination.