To determine whether the selective cerebral perfusion with cold blood is useful for repair of aortic arch aneurysm, 7 consecutive patients with aneurysms were examined (October, 1991-July, 1992). Four of 7 patients (57%) required emergency surgery due to the aortic rupture. Surgical repair was performed under the moderate core hypothermia (20-25 degrees C) to avoid prolonged cardio-pulmonary bypass (CPB), and the selective cerebral perfusion with oxygenated cold blood (16 degrees C, 350-450 ml/min) was employed for cerebral protection. The selective cerebral perfusion system was easily added to the ordinary CPB system with low priming volume (150 ml). The mean cerebral perfusion time, the mean cardiac arrest time, and the mean CPB time in this series were 93 min, 93 min, and 201 min, respectively. One of 7 surgical cases (14%) died due to the postoperative complication (multiple organ failure). Other 6 patients recovered and discharged. Successful cerebral protection and avoidance of prolonged CPB may be achieved by this unique method. The selective cerebral perfusion with cold blood may be one of the useful and reliable methods for repair of aortic arch aneurysm.