Background: Whether the safety and efficacy of triple antiplatelet strategy is superior or similar to the dual antiplatelet strategy in patients (pts) with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI) is still unclear. Methods: A total of 4,892 AMI pts undergoing PCI received either dual antiplatelet therapy (aspirin plus clopidogrel, Dual group, n=2,974) or triple antiplatelet therapy (aspirin plus clopidogrel plus cilostazol, n=1,918) . Results: The baseline characteristics were similar between the two groups. The early mortality and revascularization rate were lower in Triple group up to one month and all MACE was significantly in 8 months. Interestingly, lower in-hospital bleeding events might be due to less pts with peptic ulcer disease (0.4% vs. 0.9%, P=0.034). Conclusions: Triple antiplatelet therapy appears to be superior in preventing the MACE without increasing the major bleeding events in pts with AMI undergoing PCI compared with the conventional dual antiplatelet therapy.