Retroperitoneal spillage and infection in ballistic trauma to the large intestine is a difficult surgical problem. Experience with four consecutive cases of high-velocity gunshot wounds to the abdomen, colonic injury, and retroperitoneal fecal spillage is reviewed. The patients underwent repeat exploration of the abdomen and retroperitoneum through ventral and retroperitoneal laparostomies. All patients survived. The cavities of the posterior laparostomies were in gravitationally favorable positions, facilitating thorough debridement and drainage. Closure of the posterior abdominal wall using prosthetic materials was achieved in all patients. Retroperitoneal laparostomy is a useful adjunct in management of gunshot trauma to the abdomen with retroperitoneal fecal contamination. After eradication of sepsis, defect closure is complex. Tissue-impervious material on the peritoneal side prevents adhesions.