Objective:To study the effect of aliskiren, a direct renin inhibitor, on oxidative stress in type 1 diabetic rats. Methods: SD rats were randomly divided into four groups(n=9):control group, aliskiren[30 mg/(kg·day)] treated group,diabetic group, diabetic group treated with aliskiren[30 mg/(kg·day)]. Aliskiren was intragastrically administrated daily for 5 weeks, and the effects were compared among groups. Results:Compared with the control group, the activity of xanthine oxidase was decreased in the diabetic group(P < 0.01), the serum nitric oxide (NO) level was reduced(P < 0.01) and the aortic reactive oxygen species(ROS) were increased in the diabetic group. Compared with the diabetic group, aliskiren treatment improved these parameters(P < 0.05). Aliskiren did not modify the lower weight (P < 0.01), the higher blood glucose or HbA1C levels(P < 0.001) of diabetic group. Conclusion:Our results suggest that aliskiren can increase the antioxidant capability of type 1 diabetic rats and decrease the oxidative stress.