AbstractCholedochal cyst is a congenital malformation of the pancreatobiliary system. Its pathogenesis is not completely understood. The pathologic features are cystic dilatation of the common bile duct, normal liver parenchyma, a normal intrahepatic biliary system (except when associated with Caroli's disease), and partial obstruction of the terminal common bile duct.The presenting symptom in most children is mild intermittent jaundice. Ultrasound is the best initial investigation. Transhepatic cholangiography and endoscopic retrograde cholangiopancreatography define the extent of intrahepatic and extrahepatic disease but are not necessary studies in all patients.Traditionally, cyst enterostomy (i.e., drainage of the cyst into interposed intestine) was the standard operative procedure. More recently, cyst excision has become the procedure of choice. We employ a technique in which excision is confined to the inside of the cyst which eliminates many of the technical hazards of resection. The procedure was performed in 11 infants and children with no mortality and minor morbidity.