ABSTRACT— Caroli's disease is a rare form of fibropolycystic disease of the hepatobiliary system characterized by segmental cystic dilatation of intrahepatic ducts. It is associated with intrahepatic cholelithiasis, cholangitis and hepatic abscesses. Like other forms of fibropolycystic disease of the liver, Caroli's disease is often accompanied by cystic renal disease, specifically renal tubular ectasia or medullary sponge kidney. Adult-type polycystic kidney disease associated with Caroli's disease is rare, only one such case having appeared in the literature to our knowledge. We present a second instance of this association.