One hundred thirty six patients with penetrating colon injuries (gunshot wounds, 95; stab wounds, 41) were retrospectively analyzed. A scoring system, the Penetrating Abdominal Trauma Index (P.A.T.I.), was employed to quantitatively assess the severity of injuries in each patient. Of 67 patients with right colon injuries, 48 (72%) were treated definitively by primary repair (32) and by resection and ileocolic anastomosis (16), with minimal morbidity. In 69 patients with left colon injuries, 47 (68%) were treated by colostomy (28) and by exteriorized repair (19). Overall, exteriorized repair was successful in 74% of patients. All five mortalities (3.7%) were related to associated injuries. It is concluded that the majority of the right colon injuries can be treated definitively. Exteriorized repair should be the preferred method whenever colostomy is considered, except in severe left colon injuries requiring resection.