Aim: The efficacy of Drug eluting stent(DES) was well demonstrated for reduction of major cardiovascular events(MACE) and coronary arterial restenosis in percutaneous coronary arterial intervention(PCI). The object of this study was to evaluate whether the selective use of thin strut cobalt chromium alloy stent in large sized vessel (reference diameter > 3.0cm) has equivalent efficacy with comparison of drug-eluting stent for cardiovascular events and coronary arterial restenosis. Methods: The 7 cardiovascular centers were involved in this multi-center clinical trial. Total 218 patients with large vessel (reference diameter > 3.0cm) coronary stenosis (Diameter stenosis > 70%) were enrolled consecutively from 1, April, 2004 to 28, Feb, 2005 and assigned to DES or Cobalt chromium stent groups randomly. Result: The all patients were taken PCI successfully without major complication. 194 patients(89.0%) had finished clinical or angiographical follow-up at least for 6 months. The MACE of Cobalt chromium ally stent group was not different statistically with DES (15.9% vs 7.1%, p=0.069). But F/U coronary diameter stenosis of target lesions were siginifcantly better in DES group(DS = 39.8% vs 18.7%, p=0.00, MLD =2.08cm2, vs 2.98cm2, p=0.00) including sub-anaylsis of infarction related lesion(IRA), diabetes mellitus and simple typed lesion. Conclusion: The thin strut cobalt chromium stent may be an option but drug-eluting stent is suggested to be first choice of coronary stent in large vessel disease regardless of all types of lesion or characters of patients.