The aim of the study was to determine if estimation of serum cystatin C could replace creatinine clearance in routine determinations of glomerular filtration rate (GFR) for early detection of kidney affection in patients with cirrhosis in a case control study. According to Child- Pugh’ s classification, 20 group C and 20 group B patients i.e. a total of 40 patients were included in the study. Twenty age, sex and body mass index matched were used as controls. Serum creatinine and creatinine clearance were measured by Jaffe reaction. GFR was measured by 99m Tc-DTPA technique. Serum cystatin C was measured by particle enhanced immunoturbidimetry. Pearson correlation analyses showed that cystatin C has no correlation with age or body mass index. Moreover, cystatin C showed more significant correlation(r:-0.85, p<0.001), than serum creatinine (r:-0.32, p<0.05) with GFR measured with 99mTc-DTPA technique in patients with cirrhosis. The results demonstrated that serum cystatin C values were significantly higher in hepatorenal syndrome patients than in controls. Results showed that neither serum creatinine nor creatinine clearance were good indicators of hepatorenal syndrome(r: 0.089). Serum cystatin C level is independent of age or body mass index. Thus we suggest that serum cystatin C assay may be useful marker for early detection of renal insufficiency in hepatorenal syndrome. Also, the increase in cystatin C is higher in decompansated cirrhotic patients than in compensated cirrhotic patients.