Background: Hypertension is one of the most serious cardiovascular diseases due to its end organ complications on the heart, kidney, and brain. Hydrogen sulfide gas was shown to be synthesized in vivo and it was found to play multiple physiologic and pathophysiologic roles on different organ systems; However, its role in regulation of blood pressure is not well-understood; Thus, the aim of this study is to investigate the effects of the H2S donor, NaHS on systolic blood pressure and oxidative stress in a chronic model of hypertension. Materials and methods: Hypertension was induced by in male Sprague Dawley rats by unilateral nephrectomy followed by injection of deoxycorticosterone acetate (DOCA) (20 mg/kg) in olive oil s.c. twice weekly for 4 weeks in addition; drinking water was replaced by 1 % NaCl solution. Briefly animals were divided into three groups, 4 animals of each; sham control, hypertensive non-treated (HTN) and hypertensive treated with NaHS (HTN-NaHS) 56 μmole/kg/day in normal saline, i.p for 4 weeks. Blood pressure was measured by a non-invasive tail cuff method before induction of hypertension, after induction and after treatment with NaHS. At the end of experiment blood and aortic tissue samples were collected for assessment of malondialdehyde (MDA) and catalase enzyme activity. Results: Treatment with NaHS caused significant decrease in systolic blood pressure, decrease of MDA level in serum and aortic tissue and increase of catalase enzyme activity in aortic tissue. Conclusion: NaHS treatment reduced blood pressure and ameliorated oxidative stress in hypertensive rats.