In order to study on the distribution, metabolism and excretion of pregnenolone in fish, pregnenolone-<14>^C was injected into the dorsal aorta of goldfish (Carassius auratus) and after different survival times ranging from 5 minutes to 12 hours, the fish were subjected to whole-body autoradiography. The pregnenolone-<14>^C was rapidly taken up from the blood by various tissues. Five minutes after injection the highest accumulation of pregnenolone-<14>^C and/or its metabolites was observed in the kidney, gills, and muscle (Fig. 2). From 20 minutes up to 4 hours after injection, however, the highest uptake of radioactivity was registered in the liver, gall-bladder, and intestinal mucosa (Figs. 3-5). These results suggest that the liver plays an important role in steroid metabolism in fish as well as in mammals, and that steroid and/or its metabolites are excreted via the kidney, gills and gall-bladder. A specific accumulation of radioactivity was also observed in the ovary, interrenal gland, central nervous system, retina, and olfactory pits. Twelve hours after injection the radioactivity disappeared from all tissues other than retina and intestine (Fig. 6).