Background: Netrin-1 is a diagnostic biomarker that has been identified recently for chronic renal failure (CRF) in animal experiments. Netrin-1 levels in urine have been shown to have increased significantly at the acute kidney damage. Human studies on the relation between the CRF and plasma netrin-1 levels have not been found in the literature. This study aimed to investigate whether plasma netrin-1 levels increased in the early stages of the CRF in diabetic patients. Methods: Plasma samples from healthy volunteers and diabetic patients with and without microalbuminuria were collected after receiving consent. Netrin-1 in plasma was quantified by enzyme-linked immunosorbent assay and the data were analyzed to determine whether plasma netrin-1 correlates significantly with disease progression. Result: Plasma netrin-1 level in microalbuminuric diabetic patients was significantly higher than in normoalbuminuric diabetic patients and the control group. However, no significant difference between normoalbuminuric patients and control group was determined. Plasma netrin-1 level was significantly associated with albuminuria and estimated glomerular filtration rate, independently of age and sex. Conclusion: This study supports that plasma netrin-1 level increases significantly when glomerular damage occurs in diabetic nephropathy.