Serum concentrations of androstenedione, testosterone and dehydroepian drosterone sulfate (DHEAS) were measured in 29 patients with premature ovarian failure (POF) and an identical number of age-matched normal control subjects. The study was aimed at determining possible differences in androgen concentrations of ovarian and adrenal origin in POF patients and agematched normal menstruating controls. Serum testosterone and DHEAS con centrations in the 2 populations were not significantly different. The serum androstenedione concentration in the POF patient group (3,077.50 ± 1,122.33 pmol/1) was significantly lower than in age-matched normal control subjects (4,167.70 ± 1,381.09 pmol/1, p < 0.005), possibly reflecting the loss of ovarian androstenedione secretion and/or a subtle defect in adrenal steroido genic capacity.