The authors report a case of Caroli's disease associated with cholangiocarcinoma. The patient presented with pain and jaundice and ultrasonography disclosed multiple common bile duct stones, cystic dilatation of the extrahepatic biliary tree and a mass in the right lobe of the liver. At operation, after a frozen section demonstrated cholangiocarcinoma, a common bile duct exploration, right hepatic lobectomy and hepato-jejunostomy were performed. They review the literature on the subject and stress the fact that hepatic tumors are associated with Caroli's disease in 7% of cases. Therefore, in these patients, when a stenosis of the biliary tree is found, multiple diagnostic manoeuvres are indicated in order to exclude the presence of malignancy.