Abstract: Objective To assess the effect of large valsartan dose on urinary protein excretion and renal function in diabetic nephropathy patients. Methods The blood pressure, 24 h urinary protein, 24 h urinary albumin, 24 h urinary β₂ microglobulin, 24 h urinary IgG, serum levels of urea nitrogen, creatinine, β₂ microglobulin, potassium, and fasting blood glucose were measured in 60 diabetic nephropathy patients admitted to our hospital from 2011 to 2012 before and after they received combined antidiabetic and large oral valsartan treatment. Results The 24 h urinary protein, 24 h urinary albumin, 24 h urinary β₂ microglobulin, 24 h urinary IgG, systolic and diastolic blood pressure were significantly lower in the patients after treatment than before treatment (P< 0.05). However, no significant difference was found in serum levels of β₂ microglobulin, urea nitrogen, creatinine, potassium and fasting blood glucose before and after treatment (P> 0.05). Conclusion Large valsartan dose can protect the kidneys of diabetic nephropathy patients by improving their proteinuria and blood pressure.