We report a case of acute type A dissection with ischemic enterocolitis due to blood flow insufficiency in the superior mesenteric artery. A 67 year-old man, with medicated ischemic heart disease and hypertension, presented to another hospital with chest pain radiating to the back and epigastrium. Contrast-enhanced computed tomography revealed a type A dissecting aneurysm, that extended from the ascending aorta to the left common iliac artery, with a 50-mm diameter in the ascending aorta. Celiac trunk and left renal artery arose from the false lumen, and the superior mesenteric artery (SMA) was compressed by the thrombosed false lumen. Symptoms of acute mesenteric ischemia clearly developed. Then, a large amount of tarry stool (melena) was discharged. First, an emergency saphenous vein bypass was performed from the common iliac artery to the superior mesenteric artery at the orifice of the ileocolic artery where it was free from dissection. Then total arch replacement was performed using cardiopulmonary bypass. The patient's postoperative course was uneventful, and the abdominal symptoms completely disappeared. This case demonstrates that prompt surgical relief of ischemia in major organs is important to save lives in the cases of acute aortic dissection with ischemic complications.