After the short review of the pathogenesis, diagnosis and therapy for congenital intrahepatic cysts of the bile-duct (morbus Caroli), reference was made to the diagnostic significance of liver scintigraphy on the basis of two casuistic reports. Liver scintigraphy permits an exact localization of intrahepatic cysts as well as information regarding the course of the hepatopathy connected with morbus Caroli. In addition, 131-J-bromsulfon scintigraphy of the liver is a simple method for controlling the patency of the bile ducts. Our observations tend to indicate that preoperative and postoperative scintigraphic controls of the liver are practical for this disease.