A 62-year-old woman became progressively ill after aorto-bifemoral graft surgery. A Tc-99m hexamethylpropyleneamine oxime (HMPAO) leukocyte scan was performed because of fever and suspected graft infection. The anterior abdominal and pelvic views demonstrated marked uptake within the sigmoid colon. Follow-up studies, including CT scan and contrast intestinal x-rays, confirmed the presence of an abnormal sigmoid loop. Subsequent surgical resection and pathological examination of the sigmoid colon revealed ischemic changes. To our knowledge, detection of ischemic colitis using Tc-99m HMPAO labeled leukocytes has not been reported. Clinical and routine radiological findings of ischemic colitis are typically nonspecific and may result in delayed diagnosis that can lead to high mortality. Tc-99m HMPAO leukocyte scintigraphy may be helpful in the noninvasive diagnosis of ischemic injury to the colon, especially after aortic graft surgery.