Several endocrine functions are described which are altered in patients with human immunodeficiency virus infection. However, there is limited information available on estrogens and their function in these patients. The aim of this study was to relate the stage of the disease with urinary and serum estrogens and the influence of heroin consumption on gonadal steroids. Forty human immunodeficiency virus infected outpatients without AIDS or the clinical picture of AIDS were involved in this cross-sectional study. The subjects were divided in two groups: heroin addicts and non heroin addicts. Blood samples were taken and 24 h urines collected. Serum follicle stimulating hormone, luteinizing hormone, prolactin, estrone, estradiol, testosterone and urinary total estrogens were measured by commercially available radioimmunoassays. Prolactin levels were not affected in the patients. However, compared with controls, follicle stimulating hormone and luteinizing hormone were significantly higher for both groups tested. In contrast, the elevated serum estrone levels were significantly lower expressed in the patients with heroin abuse compared to those of the other group. Urinary estrogens in human immunodeficiency virus infected patients of both groups were found to be higher than those compared to healthy controls. Since these drugs are known to enhance estrogen levels, we conclude that other factors are modulating estrogen formation and degradation in these patients.