72 cases of diaphragm's ruptures in patients with serious combined trauma illustrated basic methods of diagnosis in this condition including X-ray, ultrasonic methods, computed tomography and thoracoscopy. In 26.3% of the patients the diagnosis was made during laparotomy or thoracotomy for massive bleeding because of injury of other organs. In the absence of bleeding the diagnosis was based on signs of the abdominal organs dislocation into the pleural cavity. The differential diagnosis between right-sided coagulated hemothorax and diaphragm's right cupula ruptures was the most difficult.