Aortoesophageal fistula (AEF) secondary to thoracic aneurysm is rare, and is usually fatal without prompt surgical intervention, with few survivors reported. Here we report a case of a 68-year-old woman late-presenting AEF successfully treated by extra-anatomic bypass grafting. Since she had already a mediastinal infection caused by AEF on admission, we performed extra-anatomic bypass grafting from the ascending aorta to the infrarenal aorta, and primary esophageal repair. The extra-anatomic bypass grafting was performed to avoid the risk to secondary graft infection and to decrease the total ishemic time induced by intraoperative aortic clamping, which is necessary when in-situ graft replacement is chosen. Although only 17 cases (including the present case) have been reported as long-term survivors, most have involved in-situ repair of the thoracic aneurysm. To our knowledge, the present case was only the second treated successfully by extra-anatomic bypass grafting. We recommend extra-anatomic bypass grafting for a case with severe infection and prolonged hypoperfusion insult caused by massive bleeding due to rupture in an aneurysm.