A 12-year-old girl with obstructive jaundice that was initially misinterpreted radiologically as having choledochal cyst is presented. A primary hydatid cyst in the wall of the common bile duct causing obstruction was found at operation. The authors emphasize that hydatid cyst should be included in the list of differential diagnoses of obstructive jaundice and cystic lesions located around the biliopancreatic junction in children. Copyright 2003, Elsevier Science (USA). All rights reserved.