A 62-year-old man with thoracoabdominal aortic aneurysm of Crawford type IA and a 61-year-old woman with triple descending thoracic aortic aneurysms were operated on under total cardiopulmonary bypass with hypothermic circulatory arrest of the lower half of the body (rectal temperature of 17-19 C) and low flow selective perfusion of the upper and lower half of the body. Low porosity woven Dacron UBE grafts without preclotting were used for the replacement of the aorta. Postoperative courses were uneventful without paraplegia and angiographic examination revealed excellent hemodynamic results.