From Nov. 1987 to Aug. 1989, 12 patients with coronary occlusive disease underwent coronary bypass surgery at the Department of Thoracic and Cardiovascular Surgery, Catholic University Medical College. The results were as follows: 1. There were 9 males and 3 females ranged in age from 25 to 69 years with a mean of 50.4 years. 2. The prevalent locations of coronary artery stenosis were left anterior descending branch [9 cases], right coronary artery[4 cases], first diagonal branch[3 cases], left circumflex artery [2 cases] in order of frequency. 3, Among 12 cases, 5 cases had an episode of previous myocardial infarction respectively. 4. We performed triple bypass operation in 3 cases, double bypass in 2 cases and single bypass in 7 cases using great saphenous vein. 5. Postoperative complications were cerebral embolism[1, died], pleural effusion[1], temporary cardiac arrest[1], supraventricular tachycardia[1] and late gastric ulcer bleeding[1]. 6. The follow up periods were ranged from 8 months to 30 months and all survivors were on antiplatelet medication showing free of angina.