Background and Objectives : A Mayo clinic quadratic (MCQ) glomerular filtration rate (GFR) equation can be accurate in estimating GFR when kidney disease is unknown. The aim of this study is to evaluate the usefulness of MCQ GFR equation predicting contrast induced nephropathy (CIN) in patients with angina pectoris undergoing coronary angiography (CAG) or percutaneous coronary intervention (PCI). Materials and Methods : One hundred seven (n=107) patients diagnosed as stable or unstable angina with normal serum creatinine (SCr) < 1.5 were enrolled. Before and at 48hours after CAG or PCI, MCQ GFR was calculated using SCr as previously described protocol. CIN was defined as 25% elevation in SCr or an absolute increase of 0.5 mg/dl (44 關mol/L). Results : Overall, CIN occurred in 14 (13.1%) patients. CIN developed in 4 (57.1%) patients with estimated MCQ GFR less than 60 ml/min but in 10(10%) patients with GFR over 60 ml/min. In univariate analysis, CIN was associated with baseline MCQ GFR (p=0.001), C-reactive protein (CRP) level (p=0.001), contrast agent volume (p=0.005), left ventricular ejection fraction (p=0.001) and low density lipoprotein cholesterol (p=0.03). In multivariate analysis, baseline MCQ GFR ��� 60 ml/min per 1.73m2 (OR=0.02, p=0.001), contrast agent volume ��� 250 ml (OR 17.1, p=0.002), CRP ��� 0.5 mg/dl (OR 4.7, p=0.037) and left ventricular ejection fraction ��� 45% (OR 0.1, p=0.02) were independent risk factors for CIN. Conclusion : Pre-coronary angiographic MCQ GFR is an useful predictor for CIN. Strong preventive strategies are needed in this high risk patients.