Abstract: The aim of this study was to examine the possible antinephrotoxic activity of rutin (vitamin P) and vitamin C in kidney of streptozotocin (STZ)-induced diabetic rats. Oral administration on rutin (100 mg/kg), vitamin C (200 mg/day) and their combination (50 and 100 mg/kg) for 5 weeks on body and kidney weights and the levels of serum glucose, insulin and creatinine in normal and STZ-induced diabetic rats were evaluated. Reactive Oxygen Species (ROS), Malondialdehyde (MDA), reduced glutathione (GSH), oxidized glutathione (GSSG) concentrations and Glutathione Peroxide (GPx), Superoxide Dismutase (SOD) and Catalase (CAT) activities were estimated in kidney. Body weights decreased and kidney weights increased significantly (p<0.001) in diabetic rats and those changes were more significantly reduced in the combined treatment group. Abnormal levels of glucose and insulin in diabetic rats were more normalized in the coadministered group. ROS and MDA concentrations were significantly (p<0.001) increased in diabetic rats. The treatments with rutin, vitamin C and their combination to the diabetic rats significantly decreased the elevated ROS and MDA levels in kidney compared to diabetic control rats. The ratio of GSH/GSSG was significantly reduced in diabetic rats and these changes were rectified significantly (p<0.001) by the combined vitamins treatments. GPx and CAT were decreased while SOD was increased in diabetic rats, however, these activities were bring back to normal in combined treated animals. In conclusion, long-term treatment with these vitamins particularly in combination as diabetic maintenance therapy may consequently control or prevent the development of diabetic complications especially diabetic nephropathy.