Study was carried out on 235 objects included 30 healthy controls, 69 normal albuminuria and 136 diabetic nephropathy. Age, sex, BMI, period of diabetes, creatinine, HbA1c, urinary albumin levels (protein/24h, MAU) and serum cystatin C were done. To campare with normal albuminuria and heathy groups, the serum cystatin C levels increased in diabetic nephropathy group. The increased cystatin C levels was correlated with stage of diabetic nephropathy, reaching highest levels in renal failure patients. There was association between serum cystatin C levels and the age of patients, period of diabetes in early diabetic nephropathy stage. The association between serum cystatin C levels and sex, BMI was not significant.