Sixty percent of 139 patients with biliary atresia who underwent hepatic portoenterostomy (Kasai operation) from 1965 to 1994 became jaundice-free after the operation. Portal hypertension, which was confirmed by endoscopic observation of esophageal varices and/or thrombocytopenia (less than 100 x 10(3)/mm3), developed in 50% of unicteric long-term survivors. Esophageal varix was found initially between 11 months and 5 years of age in more than 70% of these portal hypertensive patients. On the contrary, thrombocytopenia developed at 6 years or older age in 63% of the patients. The incidence of portal hypertension was significantly lower in the patients whose serum bilirubin decreased less than 2mg/dl at 3 months after surgery than in the patients whose bilirubin stayed over 2mg/dl at the same postoperative time. Furthermore, re-do operation related significantly to the incidence of portal hypertension in jaundice-disappeared patients. Prophylactic endoscopic injection sclerotherapy and/or variceal ligation were sufficiently effective in the management of esophageal varices. Partial splenic embolization as well as splenectomy seems to be a treatment of choice for hypersplenism.