Cardiovascular diseases and in particular coronary atherosclerotic disease are the leading cause of mortality and morbidity in the industrialized countries. Coronary atherosclerosis has been recognized for over a century and it was the subject of various studies. Pathophysiological studies have unravelled the interactions of molecular and cellular elements involved in atherogenesis; during the last decades the basic research has focused on the study of the instability of atherosclerotic plaque. Plaque rupture and resulting intracoronary thrombosis are thought to account for most acute coronary syndromes including ST - segment elevation myocardial infarction and non ST - segment elevation myocardial infarction. This is a brief review of the pathophysiology of atherosclerotic plaque development.