From April 1990 to December 1993, 13 patients (8 males and 5 females; mean age, 62 years) who underwent surgery for DeBakey type I aortic dissection, were studied to determine pre- and postoperative complications due to original dissection and residual dissection. Ascending aortic replacement had been performed in 9 patients and replacement of the ascending aorta and aortic arch in 4. Preoperative complications were aortic regurgitation (AR) in 3 cases, shock in 4, cardiac tamponade in 5, myocardial ischemia in 2 and spinal cord ischemia in 1. Postoperative complications were visceral and limb ischemia in 1 case, left leg ischemia in 1, spinal ischemia in 2 and worsening AR in 1. The postoperative 30-day survival rate was 85% (11/13). Two patients who underwent urgent ascending aortic replacement with simultaneous coronary artery bypass grafting died within 30 days after surgery. One patient with visceral and limb ischemia died in the hospital. Two patients with spinal ischemia survived but became paraplegic. Cardiac, visceral or spinal ischemia was a common problem in this series. All four patients who underwent ascending aortic replacement with simultaneous aortic arch replacement were alive for 30 days after surgery. The incidence of residual dissection may be reduced by replacing the ascending aorta concomitantly with the aortic arch rather than replacing the ascending aorta only. If a patient with DeBakey type I aortic dissection is in fair preoperative condition and elective surgery is possible, replacement of the ascending aorta and the aortic arch should be considered.