A total of 205 female infertility patients were investigated for hormonal causes of infertility after other factors such as tubal dysfunction or andrologic disorders had been ruled out. Increased androgen serum levels were found in 72/205 (35.1%) of females. In 28/205 (13.7%), elevated prolactin serum levels were noted. 119/205 (58%) of patients suffered from primary infertility versus 86/205 (42%) with secondary infertility. The incidence of hyperandrogenemia was higher in the primary infertility group (p less than 0.0015). No differences relative to hyperprolactinemia were noted between the two groups. Computerized tomography and sonographic methods did not reveal tumors in any of the subjects where serum concentrations of testosterone and dehydroepiandrosterone sulfate were greater than 2 ng/ml and 7 micrograms/ml, respectively. Present data combine to suggest that the determination of androgen serum levels is of major importance when investigating infertile patients.