Traumatic surgery at the present time is of great interest to physicians. Traumatic retroperitoneal rupture of the duodenum, though rare, is a condition well worth attention. Reports show plainly that too frequently operation is delayed and that the lesion may be missed at operation, and that the prognosis is poor because of these factors. Thus it behooves every surgeon who is called on. to treat patients as surgical emergencies to have some established knowledge of duodenal ruptures into the retroperitoneal tissues and to be able to find an occult lesion when exploring the peritoneal cavity. He will be helped by knowledge of technical factors gained from reports of successful or unsuccessful cases. Reports1 from the present conflict have recorded cases of intestinal rupture from "immersion blast force." Study of these reveals the mechanics of many of the retroperitoneal duodenal injuries. Experimental and physical data suggest that intestinal rupture caused