Sulfurylation of many steroid hormones has been found to occur in several tissues of the fetal and adult human. Because the production of prodigious quantities of dehydroepiandrosterone sulfate in the developing fetus is believed to be of signal importance in the hyperestrogenic state that is characteristic of human pregnancy, we sought to define the tissue sites that contain dehydroepiandrosterone sulfotransferase (DST). To this end, antibodies directed against purified human liver DST were employed for the immunohistochemical localization of DST in several fetal tissues. Abundant DST was found in the fetal and neocortical zones of the adrenal cortex, liver, testis, and intestine. Collecting ducts of the kidney were weakly positive for DST. DST immunostaining was not observed in spleen, thymus, lung, brain, heart, stomach, pancreas, or skeletal muscle. The tissue localization of DST immunoreactivity is consistent with the reported localization of enzymatic activity determined during in vitro studies on sulfurylation of C19 and C21 steroids. On the other hand, DST localization does not correspond as well to the sites of estrogen sulfurylation found by others. These data suggest that a single enzyme may be responsible for sulfurylation of C19 and C21 steroids in the developing human.