Background Cystatin C(Cys-C) is an accurate marker of renal function. Previous studies indicated that serum cystatin C was associated with cardiovascular disease(CVD) and events. The causes of the association are unknown largely. We evaluated the association between serum Cys-C and CVD in patients without known renal dysfunction. Methods Subjects(n=213) were categorized into quartiles of serum cystatin C(1st : <0.8mg/L, 2nd : 0.8-0.9mg/L, 3rd : 0.9-1.1mg/dL, 4th : >1.1mg/L) and compared for the extent of cardiovascular disease after coronary angiography. Significant stenosis was defined as over 50% of a vessel diameter. Chronic renal failure and serum creatinine over 1.3 in women, 1.5 in men were excluded. Past medical history, lipid profile, cardiac enzyme and eGRF by MDRD equation were evaluated. Results Sex, diabetes, hypertension were not different significantly between each quantiles. Age in highest quantile was significantly higher than the lowest quantile.(p<0.0001) eGRF and HDL were significantly higher in lowest quantile than in highest quantile(p<0.0001). Percutaneous coronary intervention was higher in lower quantile than in higher quantile(p=0.035). Cys-C was positively correlated with age(r=0.415, p<0.0001), creatinine(r=0.464, p<0.0001) and negatively with eGFR(r=-0.506, p<0.0001), HDL(r=-0.204,p=0.004). Conclusion There were significant correlations between cystatin C values and age, HDL and eGFR. Cystatin C showed a difference between lowest and highest quantile but didn���t show the significant graded association with the extent of coronary disease.