The case of an 11-year-old girl who developed acute abdomen after an accidental fall over an iron bar is reported to discuss the diagnostic features and treatment options for traumatic rupture of a choledochal cyst (CC) in children. The patient was admitted to the emergency department with complaints of vomiting and abdominal pain. Physical examination revealed tenderness at the right upper quadrant of the abdomen. Computed tomography findings revealed a rupture of a type IV CC and laceration of the liver. Cholecystectomy, total excision of the cyst, and hepaticojejunostomy were performed. Traumatic rupture of a CC is extremely rare in children, and only 2 cases have been reported. Because patients can be misdiagnosed as experiencing liver hematoma, computed tomography should be performed for all patients with free fluid in the abdomen and cystic mass on the initial evaluation.