A successful resection of dissecting thoracoabdominal aortic aneurysm is presented in a patient who had undergone kidney transplantation 20 months previously. Because the transplanted kidney is more sensitive to ischemia than the normal kidney, a femoro-femoral bypass with a pump oxygenator was used for perfusion of the transplanted kidney during crossclamping. During the clamping time of 1)8 minutes, kidney perfusion was maintai ed with a perfusion pressure of (19 to 31) 27mmHg and the flow was 0.53 to 0.81 L/min. 32mm sized Hemashield (22 Cm in length) was interposed. The postoperative course was uncomplicated. We believe that performing the femoro- femoral bypass with a pump oxygenator is an effective and simple method for renal and spinal protection in such operations.