Background: The safety and efficacy of ���high loading dose��� with 600 mg compare to ���intermediate loading dose��� with 450mg had not been studied in all comers undergoing percutaneous coronary intervention (PCI) with drug-eluting stents (DESs) in Asian population. Method: The study population consisted of 785 consecutive patients (pts) who underwent PCI with DES from Sept 2004 to February Jan 2010. Clopidogrel loading dose was decided by physician���s preference. In-hospital outcomes and major clinical outcomes of high loading dose (600mg group) were compared with those of intermediate loading dose (450mg group) up to 1 year. Results: Out of 785 pts, 510 pts (67.3%) received 600mg of clopidogrel loading before PCI. Pts in the 600mg group had similar baseline characteristics as compared to 450mg group except more smokers (51.0% vs. 42.5%; P=0.014), ostial lesions (30.2% vs. 22.5%; P=0.024), lower usage of cardioprotective medications including B-blockers (46.6% vs. 57.2%, P=0.006) and ARB (15.6% vs. 24.5%, P=0.002) in the 600mg group whereas they received higher dose of unfractionated heparin (UFH,4227.6짹1889.5 U vs. 3846.7짹2228.5 U; P=0.012) and more GpIIb/IIIa receptor blocker (9.8% vs. 4.8%; P=0.038). After the adjustment of baseline differences, there were similar 1 year clinical outcomes between the two groups (Table). Conclusion: Intermediate loading dose of 450mg Clopidogrel was similarly safe and effective as compared with higher loading dose of 600mg in a series of Asian population who are undergoing PCI with DESs.