Background: Statins significantly reduce mortality in individuals with coronary artery disease (CAD), but large statin trials excluded individuals over the age of 75 years. This study evaluated the clinical effect of statin therapy on major adverse cardiac events (MACE) in elderly patients with CAD underwent percutaneous coronary intervention (PCI). Methods and Results: One hundred twenty one patients with CAD over 75 year-old (78.6짹3.3 years, M:F=65:56), who underwent PCI between Jan 2001 and Jun 2003, according to clinical characteristics, coronary angiographic findings, and mortality and major adverse cardiac event (MACE) during one-year clinical follow-up. Statin prescription was determined after PCI. Patients were divided into two groups, patients taking a statin (Group I: 45 patients, 20 male, 78.0짹2.8 years) and those not taking a statin (Group II, 76 patients, 45 male 78.9짹3.5 years). Group I had higher prevalence of hyperlipidemia (55.6% vs. 2.6%, p<0.001) and higher total cholesterol (209.9 짹 44.6 mg/dL vs. 170.1 짹 34.4 mg/dL, p<0.001) and low density lipoprotein-cholesterol (149.3 짹 35.5 mg/dL vs. 104.3 짹 27.9 mg/dL, p<0.001). There are no difference between two groups in ACC/AHA lesion type (A and B1: 55.5 % vs. 69.7%, p=NS, B2 and C: 44.5 % vs. 30.3%, p=NS), TIMI 3 flow after PCI (86.8 % vs. 78.9%, p=NS ), LV ejection fraction (56.9 짹 13.0 vs .54.3 짹 12.3, p=NS ), CRP (1.91 짹 2.71 vs. 1.21 짹 4.26, p=NS ) and number of patients of stent insertion(80.0% vs. 76.3%, p=NS ). The number of patients with event-free survival during one-year clinical follow-up was 40 (86.4%) in group I and 56 (73.6 %) in group II (p=0.03). In multiple logistic regression analysis, event-free survival was associated with diabetes (p=0.01, OR=0.03) and use of statin after PCI (p=0.03, OR=10.0). Conclusion: Statin therapy lowers MACE in elderly patients with CAD underwent PCI.