Fetal bile salt metabolism was assessed by the intravenous infusion of e114C]cholate into 6 monkey fetuses. The placental transfer, fetal plasma clearance, and fetal hepatic excretion of the administered radiolabeled bile salt were measured. Placental transfer averaged 30% of the injected dose, while biliary excretion averaged 36%. Of the amount excreted by the fetal liver, 78% was in the form of [14C]taurocholate. The findings suggest that bile salt metabolic and excretory mechanisms are undergoing developmental maturation at birth.