Resected extrahepatic remnants taken at the time of portoenterostomy were examined in a single-center review of 205 cases of biliary atresia. The morphological features of the size and number of residual ducts at the porta hepatis and the degree of inflammation at the porta hepatis were analyzed using a semiquantitative scoring system. The morphology of the common hepatic and common bile duct was classified into seven types. These features were then related to age at time of initial surgery and to survival. This showed that few or absent ductal remnants at the porta hepatis and absence of portal inflammation were predictors of poor prognosis. These histological features may represent the "burnt out" end result of the disease process. There was no correlation between age at time of portoenterostomy and either portal duct patency or portal inflammation. The common hepatic and common bile duct were variably involved in the sclerosing process, but the patterns of obliteration were not indicative of prognosis. The severity of intrahepatic biliary cholangiopathy and the extent of liver damage may ultimately be more important to survival in the long term.