We described signs and symptoms of patients who present to an Emergency Department (ED) with intestinal ischemia and compare clinical course and outcomes of patients with mesenteric vs. colonic ischemia. We retrospectively reviewed charts of 100 patients discharged from our hospital with an ICD-9 code for mesenteric or intestinal ischemia. Compared to patients with mesenteric ischemia, those with colonic ischemia were older (61 vs. 77 years, respectively; p = 0.002), were more likely to present with gastrointestinal (GI) bleeding (11 vs. 90%, respectively; p < 0.001), but were less likely to report abdominal pain as their primary complaint (89% vs. 10%, respectively; p < 0.001) or to receive a correct ED diagnosis (75% vs. 9%, respectively; p < 0.001). Patients with colonic ischemia frequently presented with gross GI bleeding, and were often misdiagnosed in the ED. For timely treatment of a potentially serious condition, the diagnosis of intestinal ischemia should be considered in ED patients presenting with GI bleeding and appropriate risk factors.