Purpose To investigate effect of valsartan on expression of Notch pathway and production of extracellular matrix. Methods Urine protein and production of extracellular matrix were measured after diabetic mice were treated with valsartan. The levels of Jag-ged1, Notch1, Notch intracellular domain 1 (NICD1), transforming growth factor-β1 (TGF-β1), TypeⅣcollagen and Laminin were determinated by immunohistochemistry, Western blot and real-time PCR. Results Valsartan suppressed urine protein and production of extracellular matrix in diabetic mice (P<0. 05). Valsartan also inhibits overexpression of Jagged1, Notch1, NICD1, TGF-β1, Type Ⅳ collagen and Laminin in glomerular tissues of diabetic mice (P<0. 05 or P<0. 01). Conclusion Valsartan inhibits activa-tion of Notch pathway in glomerular tissues of diabetic mice, inhibits production of extracellular matrix in glomerulus and delays glomer-ulosclerosis.