17 patients with a Caroli's syndrome are reviewed with emphasis on clinical features and late results (follow-up: 2-10 years). The group consists of 9 women and 8 men ranging in age from 17 to 80 years (mean of 42.6). 14 patients had a diffuse form, 5 of whom had periportal fibrosis with secondary biliary cirrhosis, which in 3 cases resulted in a portal hypertension with hepatic failure. In only 3 cases the dilatation was limited to the left lobe of the liver. 9 of the patients had previously undergone surgery in the form of cholecystectomy and choledocholithotomy elsewhere. The disease was complicated by lithiasis (14 intrahepatic, 9 extrahepatic). Curative treatment was only possible in the 3 patients with unilobar Caroli's syndrome (partial liver resection). In 5 patients we performed a cholecystectomy and choledocholithotomy combined in 2 cases with a transduodenal sphincterotomy. There was no operative death. Endoscopic treatment consisted in removal of stones and decompression of the biliary tree by sphincterotomy in 9 cases and endoscopic retrograde biliary drainage (endoprosthesis) in 5 cases. Excepting the 3 curative operated patients who are asymptomatic respectively 2, 4 and 5 years after surgery, the remaining cases had repeated bouts of acute pains accompanied by recurrent episodes of cholangitis. A late mortality of 23.5% (4 patients) is proof of the poor prognosis of this disease.