Changes in both the urinary estrogens and androgens have been implicated as discriminants for risk of breast carcinoma. Since few studies of the plasma hormone profile have been reported, an investigation of the hormone profile of two populations, one with a high incidence, Caucasian North American, and the other with a low incidence, Bantu, of breast carcinoma was carried out. Initial results show an elevated testosterone level prior to puberty and higher estrone and estradiol levels in young Bantu women. The dehydroepiandrosterone (DHEA) sulphate and androsterone sulphate levels were comparable in the two populations. Both luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels are elevated in pre menopausal Bantu women with breast carcinoma. Data suggest considerable differences in the hormone profiles between the two populations.