From Febrary 1984 to July 1992, 138 cases of multiple valve replacements were performed at the Department of Thoracic and Cardiovascular Surgery, Dongsan Medical Center, Keimyung University. There were 81 females and 57 males, and their ages ranged from 19 to 60 years [mean age, 40.1$pm$10.9 years]. Thirteen of these patients had undergone previous cardiovascular procedures, with an average of 76.3 months between procedures[range, 3 to 180 months]. Mitral and aortic valve replacement were done in 135 patients, 2 underwent triple valve replacement and 1 underwent mitral and tricuspid valve replacement. Associated procedures were necessary in 20 patients[14.5%]. The operative mortality was 5.8% and the most common cause was low cardiac output. Late follow-up of 83% has been accomplished in 130 early survivors, with a late mortality of 5.9%. The late mortality was due to valve thrombosis in 2 patients, cerebral infarction in 1, heart failure in 1, arrhythmia in 1, and bleeding in l. Of those patients who survived, New York Heart Association functional class improved significantly[from 70% class III and IV before to 88% class I and II after]. Actuarial survival rate including all deaths was 88.8% at 8 years. The follow-up studies revealed that thromboembolism, reoperation and bleeding rate were 1.2%/patient-year, 0.85% /patient-year and 0.57%/patient-year at 8 years postoperatively. We concluded that valve thrombosis, embolism, and anticoagulant-related hemorrhage were the main risk factors of longterm survival of patients.