The effect of organ injury severity on outcome was assessed in 101 patients treated for duodenal trauma. Most patients were men (89%) and victims of penetrating wounds (93%). Grade I is minor hematoma or incomplete perforation; Grade II is major hematoma or small complete perforation; Grade III is large perforation excluding ampulla; Grade IV is large perforation at ampulla; Grade V is duodenopancreatic crunch. The injuries were as follows: Grade I (5 patients), Grade II (31), Grade III (40), Grade IV (12), and Grade V (13). Fourteen patients exsanguinated from associated vesselinjury; each had Grade IV or Grade V injury. All 36 patients with Grade I and Grade II injury had primary repair; the single death was due to liver necrosis. Most (31 patients) Grade III injuries and three Grade IV injuries were treated by primary repair alone; the three deaths were unrelated to the duodenal injury. Other major injuries were treated by duodenal exclusion (4 patients), duodenal diverticulization (6), or resection (4); the single death was unrelated to the duodenum. Primary closure is favored for minor injuries and most Grade III injuries. Severe injuries may require exclusion, diverticulization, or resection.