Rupture of the diaphragm following blunt trauma is rare in children. A late presentation of a left diaphragmatic rupture with gastric volvulus is also highly exceptional. The authors report the case of a 5-year-old boy with a left diaphragmatic rupture, who presented with acute respiratory distress and volvulus of the herniated stomach 6 months after injury. The features of this uncommon entity are discussed with special emphasis on early diagnosis. It is concluded that repeated chest radiographs during hospitalization, as well as some days after discharge, should be obtained in trauma patients to detect a slowly increasing herniation.