Coronary atherosclerosis is the most frequent cause of ischemic heart disease. The composition and vulnerability of the atherosclerotic plaque determines the development of acute coronary syndromes. In this study, 224 advanced atherosclerotic plaques were identified from the main coronary arterial branches of 10 autopsy heart specimens. The plaques were classified by American heart association (AHA) and modified American heart association classification. Vulnerability of the plaques and factors influencing vulnerability were assessed. Vulnerable plaques were mostly of Type IV category of AHA classification and of thin cap fibroatheroma type by modified American heart association classification. Inflammation was more frequent and was of a higher grade in vulnerable plaques. Calcification was predominantly of mild grade.