This article discusses congenital and acquired disorders of the bile ducts and gallbladder in infants and children. Problems, such as extrahepatic biliary atresia, that are unique to infants are covered as well as distinctive aspects of hepatobiliary disease in older children. Biliary tract disease in the fetus and neonate presents an important challenge in that not only is hepatic structure and function disturbed but also the process of normal development may be retarded or altered by the disease process.