Coronary artery disease is manifested by angina, acute myocardial infarction, sudden cardiac death, and heart failure and classified into chronic stable angina and acute coronary syndrome by pathogenesis. Acute coronary syndrome begins with the rupture of an unstable atheromatous plaque and the formation of intra-coronary thrombus. It is classified into unstable angina, non-Q wave myocardial infarction, and Q wave myocardial infarction by the severity of disturbance of coronary blood flow, the presence of myocardial injury, and the electrocardiographic (ECG) manifestations. The therapeutic strategies of acute coronary syndrome depends on the presence of ST segment elevation on ECG. Patients presenting with ST segment elevation myocardial infarction (STEMI) are candidates for reperfusion therapy (either pharmacological or catheter-based) to restore the flow in the occluded epicardial infarct-related artery. Patients presenting without ST segment elevation (NSTEMI) are not candidates for pharmacological reperfusion and should receive anti-ischemic therapy. Antithrombin and anti-platelet therapy should be administered to all patients with an acute coronary syndrome. The therapeutic strategies of chronic stable angina are to prevent myocardial infarct or death, and to control the ischemic symptoms. The new insights on the pathogenesis of coronary atherosclerosis will change the preventive measures against cardiovascular events. We have to pay attention not only to the conventional measures such as reducing the LDL cholesterol level, correcting hypertension, and prescribing anti-platelet agents, but also to the new measures such as reducing non-HDL cholesterol, and lifestyle modifications.