Backgrounds: The aim of this study is to evaluate the role of the decreased estimated glomerular filtration rate (eGFR) as a prognostic factor in patients with stable angina performing percutaneous coronary intervention (PCI). Materials and Methods: Between April 2005 and December 2009, 434 patients who diagnosed as stable angina with normal renal function [estimated glomerular filtration rate (eGFR) ���60 mL/min/1.73 m2] and performed PCI were enrolled in this study. We measured basal eGFR before PCI, eGFR at 24 hours later after PCI and at 1 year later. Group 1 was defined as patients without changes of eGFR for 1 year: Group 2 as 10% decreased eGFR at 1 year and without changes of 24 hours: Group 3 as 10% decreased eGFR at 24 hours after PCI and normalized at 1 year: Group 4 as consistent decreased eGFR. Clinical characteristics, major adverse cardiac events (MACE), including cardiac death, myocardial infarction (MI), target lesion revascularization (TLR), target vessel revascularization (TVR) and stent thrombosis (ST) were analyzed among groups. Results: There were significant difference among groups with sex, body weight (p<0.001). Patients with old myocardial infarction, low left ventricular ejection fraction and low level of high-density lipoprotein cholesterol were more common in group 4 (p<0.001, p=0.002, p=0.011, respectively). Use of angiotensin-converting enzyme inhibitors or angiotensin receptor blocker was less in group 4 (p<0.001). There was no difference among groups with MACE. During follow-up (mean duration was 425짹194 days), total MACE was observed at 6.7%. The patients with low eGFR within 24 hours, low eGFR after 1 year and gradual decline of eGFR during 1 year showed more MACE in unadjusted analysis (p=0.043, p=0.005, p=0.017, respectively). Multivariate analysis revealed that no change of eGFR during 1 year was protective factors of MACE [Odd ratio = 0.331 (95% confidence interval 0.125 to 0.88), p=0.027] after adjustment. Conclusion: The decline of eGFR after 24 hours and 1 year may not affect the clinical outcomes of patients with stable angina after PCI. However, the decline of consistent eGFR during 1 year would be prognostic factor of adverse cardiovascular events. Key Words : estimated glomerular filtration rate, major adverse cardiovascular events, prognostic factor