Gelatin impregnated Dacron graft was used without preclotting for the replacement of ascending and transverse aorta in 11 cases. The replacement of transverse aorta was performed in six patients with atherosclerotic aortic arch aneurysms and two patients with aortic dissections. The replacement of ascending aorta was performed in two patients with annlo-aortic ectasia and one patient with aortic dissection. Five of 11 patients (45%) needed emergency surgery due to the aortic rupture. Bleeding from the graft was not recognized clinically in all cases during the full heparinized cardiopulmonary bypass ranged from 153 min to 260 min. One patient (9%) with the rupture of transverse aorta died at the 7 th post operative day due to the multiple organ failure. No complication related to the graft was observed in all cases. Zero-porocity gelatin impregnated graft was useful for the replacement of aorta, especially for the replacement of ruptured ascending and transverse aorta in emergency situation.