Abstract: Ischemia/Reperfusion (IR) induces severe tissue injury mainly caused by oxidative stress. A considerable body of recent evidence suggests that oxidative stress and exaggerated production of reactive oxidant species play a major role in several aspects ischemia and reperfusion. Hypericum perforatum is a medicinal plant species containing many polyphenolic compounds namely flavonoids and phenolic acids. Because polyphenolic compounds have high antioxidant potential in this study we evaluated the effect of H. perforatum extract on renal ischemic reperfusion injury. Renal ischemic reperfusion was induced in rats by clamping the renal artery for 60 min. After 7 days of reperfusion. H. perforatum extract treatment markedly reduced renal ischemia reperfusion injury in I/R+HP 30 mg kg-1 group comparative with other treatment and sham groups.