Drug-eluting stent (DES) implatation was the major method of coronary revascularization and marked reduction in target-lesion revascularization. Stent thrombosis (ST) is a severe complication that is associated with a high incidence of acute myocardial infarction and death. To prevent ST, dual antiplatelet therapy (DAPT) with aspirin and clopidogrel is recommended for at least 12 months. The premature discontinuation of DAPT is the single most significant predictor of perioperative ST. The risk of surgical bleeding is increased approximately 20% by aspirin or clopidogrel alone, and 50% by DAPT. But the increased risk of perioperative bleeding is not necessarily associated with increased mortality or surgical outcome. Usually, the risk of a cardiovascular event when stopping antiplatelet agents preoperatively is higher than the risk of surgical bleeding when continuing these drugs, except during high risk surgery in a closed space. We remember that DES are never low risk situation for ST and aspirin must never be stopped in all patients with DES. (Korean J Med 2013;85:22-28)