Abstract: Objective:To observe the level of plasma homocysteine(Hcy) in patients with diabetic nephropathy(DN) and analyze the relationship between the level of Hcy and DN.Methods:The plasma Hcy level of 104 cases of DN including 50 case who were combined with heart and cerebrovascular diseases and 38 healthy controls was measured by enzymatic cycling; their blood glucose (Glu),serum creatinine(Scr),total cholesterol(TC),triglyceride(TG) and high-sensitivity C-reactive protein(hs-CＲP) were also measured.Results:The plasma Hcy level of patients with DN was significantly higher than that of the healthy control(P 0.01); the plasma level of Hcy and hs-CＲP in DN patients combined with cardio-cerebral vascular disease were significantly higher than that of DN patients free of heart and cerebrovascular diseases(P 0.01).Hcy was positive correlated to Scr,TC,TG and hs-CＲP (P 0.05 to P 0.01).Conclusions:The level of Hcy is elevated in patients with DN; Hcy may participate in the genesis of heart and cerebrovascular disease in patients with DN; the incidence of cardio-cerebral vascular diseases in DN patients may be reduced by lowering the plasma Hcy level.