A 55-year-old man with an acute Stanford type B aortic dissection presented with clinical signs of mesenteric ischemia. Computed tomography (CT) revealed a thrombosed false lumen in the superior mesenteric artery. At laparotomy, the dissection was found to be extending into the jejunal branches and medial colic artery. Thrombus was removed from the false lumen, and perfusion was restored with an iliomesenteric bypass, with the dissected layers tacked together in the suture line. A postoperative CT scan showed a stable diameter of the thoracoabdominal aorta and a patent iliomesenteric bypass.