Congenital cystic disease of the biliary system is a complex syndrome of ectasies of the intra-, extra- or both situation of biliary tree. This disease has an unsure etiopathogeny. It is uncommon through the third age, with a greater incidence in child, teen-ager and young adult. The goal of our study is to evaluate the symptoms, diagnosis, treatment and histological aspects of the congenital biliary cysts. We performed a retrospective study from March 1988 to July 2003 about 11 patients with this disease treated in our surgical clinic. Clinical features, methods of diagnosis and surgical treatment were assessed. All patients were females with mean age 51 years (extreme 26-77 years). The symptoms were: right upper quadrant pain--11 cases (100%), jaundice--6 cases (54.5%), fever--3 cases (27%), palpable abdominal mass--2 cases (18%), weight loss--1 case (9%). The imaging diagnosis was helpful (ultrasonography, CT, ERCP, percutaneous cholangiography and preoperative cholangiography). In concordance with Todani classification the patients were included in the following types: Ia--3 cases (27%), I b--1 case (9%), I c--3 cases (27%), IV a--2 cases (18%), IV b--1 case (9%), V--1 case (9%). All patients were operated on: after cholecystectomy and transcystic cholangiography (11 cases--100%) we performed the total excision of the cyst--9 cases (82%) with choledochal jejunostomy (Roux-en-Y)--6 cases (54.5%), choledochal jejunostomy (omega)--1 case (9%) and choledochal duodenostomy--2 cases (18%). In one case of neoplasic cyst with portal invasion we performed a cyst-jejunostomy (omega) and in one case of Caroli disease with total obstruction of the distal choledoc, the solution of choice was choledocal-duodenostomy. The microscopic pathology of the cyst wall showed: chronic intramural inflammation--9 cases (82%) and the absence of the nervous intramural terminations--1 case (9%). The additional lesions was: hepatic cirrhosis--1 case (9%) and hepatic fibrosis--3 cases (27%). We found three cases with neoplasia: malign cyst with advanced local invasion--1 case (9%), pancreatic carcinoma--1 case (9%) and gallbladder carcinoma (microscopic finding)--1 case (9%). The postoperative morbidity includes biliary fistula--2 cases (18%) and wound infection--2 cases (18%). Long-term follow-up revealed cholangitis in one case--9%. The cystic dilatations of the common bile duct is an exclusive indication for surgery as soon as it was discovered.