Background and Objective: The impact of MS on ISR and long-term clinical outcomes after PCI with stent implantation to the patients with significant coronary artery disease is not well defined. The objective of this study is to investigate the impacts of MS on the occurrence of ISRs, long-term major adverse cardiac events (MACE) including cardiovascular death, myocardial infarction, target vessel revascularizations (TVR) during 36-months follow up. Methods and Results: This was the observational retrospective study. 338 patients treated with stent implantation from Jan. 2002 to Dec. 2004 at our hospital were enrolled. MS was defined according to National Cholesterol Education Program (NCEP) Adult Treatment Panel (ATP) ��� criteria with slight modification. The prevalence of MS was 50.3% (n=170) and the follow-up duration was median 36 months. At last, 29 patients had ISR and 33 patients had MACE in the patient with metabolic syndrome, comparatively 22 patients had ISR and 21 patients had MACE in the patient without metabolic syndrome. In the survival analysis, there was no statistically significant association between the presence of metabolic syndrome and the increased risk for MACE (log-rank P=0.105) and in the multivariate Cox regression analysis, hazard ratio of metabolic syndrome to MACE was 1.643. (95% confidence interval 0.943-2.863, p=0.079) Conclusion Metabolic syndrome was not a independent predictor of increased ISR and MACE after PCI with stent implantation to the patient with preexisting significant coronary artery disease.