BACKGROUND: This study was undertaken to investigate the outcome of composite graft aortic root replacement using coronary button reimplantation technique for the treatment of aneurysms of the ascending aorta involving the aortic root. MATERIAL AND METHOD: Between April 1995 and September 2001, 54 patients having aortic root replacement with a composite valve graft using direct coronary button reimplantation were reviewed retrospectively. Left ventricular dysfunction was present in 14 patients(25.9%), aortic regurgitation in 48(89%), and Marfan's syndrome in 17(31.5%). The indications for operation were annuloaortic ectasia in 29 patients(53.7%), aortic dissection in 11(20.4%), aneurysms of the ascending aorta involving aortic root in 12(22.2%), and aortitis in 2(3.7%). Six patients(11.1%) had previous cardiac or ascending aortic operations. Concomitant procedures were arch replacement in 21 patients(38.9%), coronary artery bypass graft in 7(13%), mitral valve repair or replacement in 4(7.4%), and others in 6. The mean time of circulatory arrest, total bypass, and aortic crossclamp were 18+/-9 minutes, 177+/-42 minutes, and 127+/-31 minutes, respectively. RESULT: There was 1 early death(1.9%). Mean follow-up was 24.6+/-19.5 months. There were two late deaths(3.8%) including one death due to the traumatic cerebral hemorrhage. The Kaplan-Meier survival rate was 98.0+/-2.0% and 93.1+/-5.1% at 1 and 6 years, respectively. Two patients required reoperation owing to a false aneurysm at the root anastomosis site anda malfunction of prosthetic aortic valve(3.8%). Staged operation for dissection of the remaining thoracoabdominal aorta was performed in 1 patient. The freedom rate from reoperation was 97.8+/-2.0% and 65.3+/-26.7% at 1 and 6 years, respectively. CONCLUSION: This study suggests that composite graft aortic root replacement using open button technique is a safe and effective therapy for a variety of aneurysms of the aortic root, resulting in good early and mid-term results. Careful follow-up of all patients following composite graft root replacement is important for the good long-term results.