Three cases of congenital cystic dilatation of the common bile duct admitted to the Pediatric Department of National Taiwan University Hospital during 1945-1964 are reported. They were a one-year-five-month (Case 1), five-year-seven-month (Case 2) and two-year (Case 3) old females. Abdominal tumor was noted in Cases 1 and 2, jaundice, abdominal pain, clay-colored stool, and bilirubinuria in Case 3. Cases I and 3 were operated with choledochoduodenostomy, and uneventful post-operative courses. Case 1 was living and well when followed-up at her age of 7 years and 8 months, but with Case 3 contact was lost after her discharge. Case 2 was operated with choledochoje-junostomy but died of sudden coma and vomiting of coffee-ground-like substance the next day. A brief discussion on the terminology, pathogenesis, sex incidence, clinical picture, treatment, and prognosis of the disease is also presented.