Background: Plasma total homocysteine (Hcy) has been associated with cardiovascular risk in previous studies, and it has been considered as an independent risk factor for artherosclerotic disease. However it is still unknown plasma Hcy can be approached as a risk factor for contrast media induced nephropathy (CIN). Purpose: The aim of this study is to evaluate relation of plasma Hcy and CIN and to compare predictive value with traditional risk factors of CIN. Method: In this single center prospective study, 281 consecutive patients who underwent elective percutaneous coronary intervention were enrolled from April 2008 to June 2009. Before and 24/48hr after PCI, serum creatinine level and estimated glomerular filtration level were checked and preprocedural complete blood cell count, plasma homocysteine, hs-CRP, uric acid and urinalysis were also checked. CIN was defined as a 25% elevation or an absolute increase of > 0.5mg/dL (>44umol/L) in the serum creatinine level compare to the baseline. We defined hyperhomocysteinemia (hyperHcy) as plasma homocysteine level over 15.0µmol/L. Result: In a total of 281 patients, hyperHcy were found in 119 (37.8%) patients. Overall, CIN occurred in 21 patients (7.5%). On univariate analysis, hyperHcy were significantly correlated with CIN (hyperHcy vs. non-hyperHcy, 13.4 vs. 2.6%). Previously well known risk factors like, diabetes, older age, urine protein positive finding, higher BUN, Cr, lower eGFR, decreased EF and higher contrast amount also showed significant correlation with CIN. On multivariate regression analysis, contrast amount (odd ratio=1.015, 95% CI 1.001-1.030, p=0.038), eGFR level (odd ratio=0.936, 95% CI 0.900-0.974, p=0.001), proteinuria (odd ratio=12.503, 95% CI, p<0.001) and hyperHcy (odd ratio=5.247, 95% CI 1.534-17.940, p=0.008) were identified independent predictors of CIN. Conclusion: Same as previous studies, increased contrast agent amount and decreased eGFR level and proteinuria were significant predictive factors of CIN in this study. Moreover, this study demonstrated hyperHcy is another independent predictor of CIN.