Congenital biliary dilatation (CBD) is a relatively rare disease and highly associated with hepatobiliary malignancies due to pancreaticobiliary maljunction. For the treatment of CBD, the standard surgical method is the excision of the entire extrahepatic duct with a hepaticoenterostomy. However, in recent years, there has been an increase in reports of cancer developing in the biliary or pancreatic duct after hepaticoenterostomy. In this report, we describe the postoperative complications and carcinogenesis in 50 CBD patients according to the method of reconstruction of the bile duct. Hepaticojejunostomy (HJ) was performed in 34 patients and hepaticoduodenostomy (HD) in 16. In the HJ group, there were 7 cases of ascending cholangitis (20.6%), 3 cases of choledocholithiasis (8.8%), 4 cases of anastomotic stricture (11.8%) and 1 case of cholangiocarcinoma (2.9%). In the patient with cholangiocarcinoma, all complications including ascending cholangitis, choledocholithiasis, and anastomotic stricture were present. In the HD group, however, 2 cases of ascending cholangitis (5.9%) were recognized although choledocholithiasis, anastomotic stricture or cholangiocarcinoma were not observed. No significant differences were found in incidences of these complications between HJ and HD. It is unclear which method of reconstruction has a higher risk of carcinogenesis, however, it can be stated that hepaticoenterostomy itself is indeed one of the risk factors for biliary tract carcinoma. In any event, as several researchers have pointed out, since the incidence of bile duct carcinoma after the resection of the extrahepatic bile duct in CBD patients is very high compared to natural control, a long-term follow-up of the patient is necessary.