Intrauterine ligation of the common bile duct was carried out in ten fetal lambs at approximately 80 days gestational age. Six of the fetal lambs survived until term and were sacrificed at varying periods until the 36th day of life. The lesion which developed resembled a “correctable” type of extrahepatic biliary atresia [Kasai type 1 (b)]. The lining epithelium was either totally or incompletely denuded in the blind end of the common duct proximal to the obstruction.