In European countries, choledochal cysts are rare anomalies of the bile tract. At the Surgery Department of the University Hospital Ostrava, a case of a patient with cystic lesion of the pancreatic head was solved. According to ultrasonography and computer tomography it was assumed to be a pancreatic pseudocyst. Only after a complete additional examination of the pancreatico-biliary system, was it diagnosed Ia-type cystic dilatation of the common bile duct, accompanied by stenosis in its terminal part. With regard to the age of the first clinical symptoms, their character and histopathological findings, congenital origin is assumed in both of these anomalies. After provisional percutaneous transhepatic biliary drainage, a duodenohemipancreatectomy was performed with complete cyst excision. Until now, nine months later, the patient has shown absolutely no clinical difficulties.