 Cilostazol is an kind of oral antiplatelet agent with a rapid onset of action that selectively inhibits phosphodiesterase III, a mechanism different from adenosine diphosphate ADP receptor antagonists. Previous studies had suggested that cilostazol has lipid-modifying and vasodilating effects in addition to antiplatelet effects. From those experimental and clinical backgrounds, we assumed that triple antiplatelet therapy with aspirin, clopidogrel, and cilostazol might have a beneficial effect on the prevention of atherothrombosis complications following coronary stenting. Therefore, we evaluated the safety and efficacy of triple antiplatelet regimen of aspirin, clopidogrel and cilostazol compared with dual antiplatelet regimen of aspirin and clopidogrel in patients with acute coronary syndrome undergoing successful coronary artery stenting. 