Twenty-six specimens of normal human endometrium were obtained for studies of [3H]benzo[alpha]pyrene metabolism in short-term organ culture. The tissues were capable of converting benzo[alpha]pyrene (BP) to oxygenated derivatives which co-chromatographed with dihydrodiols, quinones and monohydroxy derivatives of BP. A sulfate conjugate of a monohydroxy BP was also found among the acetone/ethyl acetate soluble products. When the acetone/ethyl acetate soluble metabolites were analyzed using high-pressure liquid chromatography (HPLC), the proportion of metabolites were found to vary greatly from specimen to specimen. Eight women smoked cigarettes but the BP metabolite profiles from organ cultures of endometrial tissue from these women did not differ from those who did not smoke. The average value for sulfate conjugates of monohydroxy BP was significantly lower in endometrial tissue from three postmenopausal women (ages 49, 57 and 58) than among premenopausal women. Specimens from premenopausal women which had been in organ culture for 2 weeks prior to the addition of [3H] BP produced metabolite profiles similar to those of specimens from postmenopausal women with a greatly reduced proportion of BP-phenol sulfate conjugates. These data suggest that the absence of hormonal stimulus (i.e., advanced age or conditions of organ culture) may affect the metabolism of BP in human endometrial tissue.