Ischemic injury to the rectum is rare owing to its rich vascular supply, and is seldom seen in clinical practice. Risk factors include major vascular occlusive disease, disruption of collateral circulation, and low flow state. It is of paramount importance to diagnose this entity early in its course. Although CT scan can suggest the diagnosis and identify other causes of clinical deterioration, colonoscopy remains the key test in diagnosing and determining the extent of ischemic change. Endoscopic findings and the overall clinical picture determine patient management. Treatment is nonoperative for nongangrenous ischemic proctocolitis, whereas surgery is necessary for gangrenous, transmural rectal ischemia. Over a 20-year period, a retrospective review of cases of acute rectal ischemia were analyzed. Aortoiliac occlusive disease accounted for nearly one-half the cases (7/15), and 40 per cent (6/15) was secondary to a low flow state. In our series, two-thirds of the cases involved transmural necrosis of the rectal wall (40% mortality) and the remaining one-third presented with patchy ischemic changes (20% mortality).