The results of a prospective protocol for penetrating injuries of the colon in 252 patients are presented. The protocol emphasized definitive management of the injury by repair, resection and anastomosis or exteriorized repair. Colostomy was reserved for left colon injuries requiring resection or for delayed treatment. Two hundred nineteen patients (86.9%) had definitive treatment by repair (N = 159), resection and anastomosis (N = 26), or exteriorized repair. This was successful in 205 patients (93.6%). Three patients had anastomotic leak after repair or ileocolostomy. Eight of the 34 patients with exteriorized repair had suture-line breakdown and 26 (76.5%) patients avoided a colostomy. Injury severity indices (anatomic: Abdominal Trauma Index and Flint grading of colon injury) were higher in the exteriorized repair than in the repair group. Postoperative abdominal abscesses occurred in 43 patients (17.1%). A multiple regression analysis identified the Abdominal Trauma Index (P < 0.0001) and the presence of colostomy (P < 0.0004) as significant independent factors in association with this complication. Mortality from sepsis was 2.4 per cent (6 patients) and in only one patient was the death directly related to colon injury management. We conclude that the majority of colon injuries can be managed by repair or resection with anastomosis. End colostomy is unavoidable in Flint 3 injuries of the left colon. In other situations, ileocolic or colocolic anastomoses appear to be safe in hemodynamically stable patients. Loop colostomy has a role in delayed treatment, but can be replaced by an exteriorized repair in Grade 2 colon injuries that do not require resection.