Choledochal cyst is a rare congenital dilatation of the common bile duct, often associated with a congenital or acquired dilatation of intra-hepatic ducts. The classic symptoms of abdominal mass, pain and jaundice is rarely seen during childhood. Some children may not show symptoms for years. In most patients the diagnosis can be confirmed by using ultrasound pictures or by injecting a radioactive substance and performing a tomography scan which gives an "image" of the abnormal duct. Echinococcus granulosus is often seen in the pediatric surgical practice in endemic areas, and present with various clinical and surgical pictures such as obstructive jaundice. We had under our care a 2-year old girl who choledochal cyst with the posterior wall of choledochus, which resulted extrahepatic ductal obstruction and choledochus displaced anterolaterally. Any suspected radiologic lesion observed in infant, or child patient in an endemic area should be evaluated for hydatic cyst.©2008, Firat University, Medical Faculty.