To define long-term prognosis of children who underwent surgery for biliary atresia, a retrospective study was undertaken in 122 children who underwent one of the Kasaï procedures between 1968 and 1977. Forty of the 122 children (32.7%) were alive after 10 years. Firm hepatomegaly was present in 31 and splenomegaly in 29 children. Serum bilirubin or all liver function tests were normal in 21 and 11 children, respectively; survival rate decreased with the age at operation, but no significant difference was observed in the rate of children surviving with normal serum bilirubin whether they underwent surgery before age 2 months or between 2 and 3 months. Twenty-four had esophageal varices and 15 experienced gastrointestinal bleeding. Normal liver-function tests and absence of portal hypertension were observed in 11 of 122 children. These results indicate that Kasaï's procedures were helpful in a significant proportion of children with biliary atresia who underwent surgery during this period. However, 80% of children who initially underwent surgery with Kasaï's procedures should eventually undergo liver transplantation.