The source of the remarkably high prostate citrate level was investigated in prostate fragments. L-Aspartate and .alpha.-keto-glutarate formed oxaloacetate through transamination. Neither pyruvate nor acetate was as effective as palmitate in increasing the citrate level. Apparently the source of citrate in rat ventral prostate is oxaloacetate from amino acid transamination and acetyl CoA from fatty acid oxidation and carbohydrates contribute little to citrate production in ventral prostate.