Avian liver is structurally different from that of mammal. There are only a few reports about the ultrastructure of the hepatic vessels and bile duct in birds. Casts of the hepatic vessels and bile ducts in chicken and duck were examined by a scanning electron microscope (SEM) to provide further detail. The sinusoidal vessels formed regular three-dimensional networks but the replicated bile ducts formed irregular ones. There was a dense plexiform network around each tubular cavity in biliary casts. This biliary plexus formed around a small branch of the portal vein. It was the transition between the bile capillaries and ductules. The present study shows that the liver of chicken and duck had the characteristic structure at the peripheral part of biliary system, i.e., biliary plexus.