The etiology of biliary atresia is not due to a congenital malformation but rather to a continuing process beginning in utero that affects not only the extrahepatic biliary ducts but also the intrahepatic parenchyma. Over the last decade, the outlook for patients who were previously felt to be uncorrectable has been significantly improved by Kasai's operation. Successful biliary reconstruction depends on early diagnosis and treatment (before three months of age). The essentials of hepatic portoenterostomy consist of excision of the entire extrahepatic duct structure with anastomosis of an intestinal conduit to the area of the transected duct at the liver hilus. After operation, many patients experience complications, including cholangitis, portal hypotension, and vitamin deficiencies. Despite these difficulties, growth and development continue on a relatively normal course, and long-term survival has been accomplished in many children. For those in whom biliary drainage is not achieved or with significant parenchymal damage, liver transplantation should be considered as part of ongoing care.