The objective of KASAI's operation is to obtain a postoperative bile excretion and to maintain an internal biliary fistula. The purpose of this report is to study the relationship between the liver histopathology and the postoperative bile flow and survival. From july 1976 to january 1990, 66 patients underwent a corrective operation for biliary atresia. In 24 patients we performed a KASAI's operation with internalization of the biliary conduit, 36 with externalization, four gall-bladder KASAI and two liver biopsy. The mean age at operation was 66 days and postoperative bile excretion was obtained in 43 of them (66 per 100). The survival rate was 70 per 100. The liver histopathology shown: minimum portal fibrosis (7.8 per 100), moderate (49 per 100) and severe (43 per 100). We found bile ducts in 30 patients (46 per 100), in three bile ducts were less than 50 mu, in 15 between 50 and 100 mu and more than 100 mu in 12. We did not found statistic correlation between grade of liver fibrosis size of bile duct and postoperative flow. We found a statistic correlation between the presence of bile ducts and postoperative flow (p less than 0.05).