Backgrounds: Aggressive platelet inhibition in patients with ST-segment elevation myocardial infarction(STEMI) undergoing primary percutaneous coronary intervention (PCI) is crucial for myocardial salvage and improvement of survival. Sarpogrelate HCl(AnplagTM, Yuhan, Korea) is a selective 5-HT receptor antagonist, which demonstrates potent antiplatelet activity. In this study, we investigated whether this agent can be beneficial in STEMI patients undergoing primary PCI, as a part of pretreatment regimen. Methods: From January 2008 to December 2009, a cohort of 119 patients who have underwent primary PCI for acute STEMI in our institution were evaluated. All the patients took aspirin 300mg and clopidogrel 600mg before PCI. Among them, 53 patents took additional sarpogrelate 300-600mg(Group I), while others did not(Group II). Patients in group I had taken sarpogrelate 300mg qd after PCI at least for 1 month. Demographic, clinical and angiographic parameters, as well as clinical outcomes were compared between 2 groups. Results: There were no statistical differences between two groups in terms of age, sex, location of MI, LV ejection fraction and Thrombolysis in Myocardial Infarction(TIMI) flow before/after PCI. There was a lesser percentage of diabetes in group I than group II(22.6% vs 40.0%, p=0.05), whereas smoking status was higher in group I than group II(75.5% vs 69.2%, p=0.004). Peak CK-MB levels were greater in group II than group I(347.6짹267.4 vs 198.40짹166.10, p=0.001). There showed trends toward lesser percentage of 12-months composite cardiac outcome(death, MI, stent thrombosis, target-vesel revascularization) in group I than group II(9.4% vs 18.2%, p=0.199), without statistical significance. Conclusion: The loading-dose of sarpogrelate did not showed better clinical outcome, but reduced myocardial damage after primary PCI. Further prospective, randomized study is warranted.