A 3-year experience with diaphragmatic disruption secondary to blunt trauma was reviewed. Seventy-five per cent of the disruptions were on the left side and the incidence of associated intra-abdominal and thoracic injuries was 100%. Disruption occurred in two distinct anatomic positions: 1) through the central tendon; 2) at the lateral costal insertion. Diagnosis was usually made by plain X-ray films of the chest, occasionally with the aid of fluoroscopy. Difficulty was encountered making the diagnosis preoperatively, especially when there was significant hemothorax and/or pulmonary contusion. Angiography was diagnostic in three cases. Careful examination of the diaphragm in all blunt abdominal cases is essential to avoid delay in diagnosis. In the patients with an associated ruptured hollow viscus there was high incidence of empyema leading to severe morbidity. In such cases concomitant thoracotomy at the time of definitive therapy should be considered. The mortality of this injury is primarily related to the incidence of associated injuries and pre-existing, nontraumatic disease. Diaphragmatic disruption rarely occurs alone in blunt trauma. Laparotomy is required for control of hemorrhage in most cases.