Traumatic diaphragmatic injuries in infants and children are uncommon. Late presentation of such an injury is well recognised in adults but is exceptionally rare in children. Because of the increased compliance of the thoracic cage in children, rupture of the diaphragm can occur without signs of external injury. Morbidity and mortality can be minimized by a high index of suspicion, prompt recognition, and surgical repair of even the smallest diaphragmatic injury. We present a case of delayed presentation of traumatic diagphragmatic hernia in a boy of 10 months.