ACC/AHA/SCAI Guideline recommends for administration dual antiplatelet therapy after drug-eluting stent (DES) to prevent restenosis and stent thrombosis in patients with percutaneous coronary intervention (PCI). Recently triple antiplatelet therapy including cilostazol is known to reduce restenosis and stent thrombosis significantly after DES implantation. However, there is lack of data providing the efficacy of triple antiplatelet therapy. The purpose of this study is to evaluate the clinical effects of the triple therapy after DES implantation compared with the dual therapy. This retrospective study collected data from medical charts of 251 patients who received DES implantation between Jul 2006 and Jun 2008. They received either dual antiplatelet therapy (N = 154 clopidogrel and aspirin; Dual group) or triple antiplatelet therapy (N = 97 cliostazol, clopidogrel and aspirin; Triple group). Major adverse cardiac event rates (MACE, included total death, myocardial infarction, target lesion revascularization) at 12 months, 24 months, stent thrombosis, rates of bleeding complications and adverse drug reactions were compared between these two groups. Compared with the dual group, the triple group had a similar incidence of the MACE rates at 24months (12.3% vs. 12.4%, p = 0.99). There is no difference in overall stent thrombosis between two groups (Dual group 2.6% vs. Triple group 4.1%, p = 0.5). Subgroup analysis showed that diabetic patients got more benefit in reducing MACE rates but, there is no statistical difference. Bleeding complications and adverse drug effects were not different significantly. As compared with dual antiplatelet therapy, triple antiplatelet therapy did not reduce the 12-months, 24-months MACE rates and stent thrombosis. Bleeding complications and adverse drug effects were not different.