Forty cases of coronary artery bypass grafting treated at the Department of Thoracic and Cardiovascular Surgery, SNUH, Korea were compared with forty cases of the procedure treated at University of Alberta Hospital, Canada, in terms of pathoanatomy. That showed no difference in sex ratio between Korean and Caucasian the average ages, however, were 50.4 years and 60.9 years respectively [p< 0.005]. The leading cause of angina at presentation was unstable angina in Korean, but it was post-infarction angina in Caucasian instead. The incidences of single-vessel disease and double-vessel disease were similar in both countries, but the incidence of so-called triple-vessel disease was higher in Caucasian while left main coronary artery disease was more prevalent in Korean [0.01< P, 0.005]. < The internal diameters of surgically available coronary artery branches had similar characteristics and no significant statistical differences were found between them. The predilection sites of stenoses were proximal left anterior descending artery, left main coronary artery, proximal left circumflex artery and proximal right coronary artery decreasing in incidence respectively, in Korean. The myocardial perfusion score were 6.80 in single-vessel disease, 7.56 in double-vessel disease, 11.27 in triple-vessel disease and 9.77 in left main disease respectively, in Korean.