Left thoracotomy with spiral incision is conventional approach for the repair of descending and thoracoabdominal aortic aneurysms. Because the aneurysms' locations and ranges are various, case-oriented approaches including body postures and the positions of thoracotomy are necessary. Preoperative computed tomography assessment of aneurysms is important for decision making of both operative indication and approach. Given the patient laid in a right semi-decubitus position, the crossing point of the vertical line from the aneurysm and the thoracic wall is the center of intercostal thoracotomy. Depending on the replacing range of the aneurysm, the incision is extended into the contiguous intercostal spaces with crossing ribs. For total arch replacement from left thoracotomy, additional transverse or oblique sternotomy from left 4th to right 3rd or 4th intercostal space may be effective to expose proximal arch. For thoracoabdominal aortic replacement, the costal arch is transected in the 6th or 7th intercostal level and a retroperitoneal space is dissected to expose the aneurysm. For one-staged total aortic replacement from ascending to thoracoabdominal aorta, straight incision with rib-cross approach may be effective. By incising subtotal intercostal muscles along thoracotomy, preservation of the latissimus dorsi muscle is possible and effective to spare collateral flow of spinal cord.