From 1959 through Jun. 1988, 2094 cases of various Cardiovascular diseases were operated, which were consisted of 1215 open heart surgery under extra-corporeal circulation or hypothermia and 879 conventional Cardiovascular Surgery at Department of Thoracic & Cardiovascular Surgery in National Medical Center. There were 1111 congenital heart anomalies and 983 acquired cardiovascular diseases. Among 1111 congenital cases, acyanotic cases were 748 and cyanotic cases were 363. In acquired heart cases, valvular heart diseases [702 cases] were the most frequent and a small No. of cardiac tumor and coronary artery diseases were included. Overall operative mortality was 9.3%, consisting of 4.6% for acyanotic anomaly, 20.6% for cyanotic anomaly and 8.7% for acquired heart diseases. In open heart surgery, overall mortality was 11.6% and 6% in conventional cardiovascular surgery.