Background:Whether the safety and efficacy of triple antiplatelet strategy is superior or similar to the dual antiplatelet strategy in patients (pts) with acute ST elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) is still unclear. Methods:Total of 2,404 STEMI pts undergoing primary PCI received either dual antiplatelets (aspirin plus clopidogrel, Dual group, n=1,432) or triple antiplatelets (aspirin plus clopidogrel plus cilostazol, Triple group, n=972) groups.1 month & 6 month outcome were compared. Results:Baseline characteristics were similar between the two groups.Incidence of in-hospital cardiac death was significantly lower in Triple group (2.0% vs. 3.4%, P=0.041) with no statistical difference in bleeding events.Triple group showed significantly lower incidence of All MACE through the 6 months��� follow-up (Table). Conclusions: Triple antiplatelet therapy appears to be superior compared with the dual antiplatelet therapy in reducing early mortality and the MACE without increasing major bleeding event in pts with STEMI undergoing primary PCI.