The distribution of binding sites for Dolichos biflorus agglutinin (DBA) was studied by histochemical staining in the embryonic mouse liver. The liver primordium consists of cranial and caudal diverticula. DBA bound to the pseudostratified endodermal cells of the caudal hepatic diverticulum, and also to some endodermal cells of the cranial one. Most extrahepatic bile duct cells and all epithelial cells of the gall bladder were consistently DBA-positive. In intrahepatic bile ducts and their precursors, the DBA binding sites showed a patchy distributon. Most hepatocytes were DBA-negative, though some young hepatocytes were DBA-positive. The results suggest that DBA binding sites are useful markers of epithelial cells of the gall bladder and the bile ducts, especially the extrahepatic bile duct. Differentiation of bile duct cells was also discussed with special reference to the developmental change of the distribution of the DBA binding sites.