Nephrotoxicity is a major complication of gentamicin (GEN), which is widely used in the treatment of severe Gram-negative infections. Reactive oxygen species are important mediators of GEN-induced nephrotoxicity. Because of the strong antioxidant properties of pomegranate extract (PE), we evaluated the protective effect of PE against GEN-induced nephrotoxicity. Thirty-two adult male rats were randomly divided into four equal groups: (1) controls; (2) treated with GEN for 14 consecutive days (100 mg/kg/day); (3) treated with GEN plus distilled water; and (4) treated with GEN plus PE (100 mu L). After 15 days, the rats were killed and their kidneys were taken, and blood analysis was performed. Tubular necrosis and interstitial fibrosis scores were determined histopathologically; and biochemically, nitric oxide (NO), malondialdehyde (MDA), and reduced glutathione (GSH) levels in kidneys were determined. Urea, creatinine, Na+, and K+ levels were investigated in the blood analysis. Statistical analyses were made by the chi-square test and analysis of variance. Serum urea and creatinine levels were significantly higher in rats treated with GEN alone than rats in the control and the GEN + PE-treated groups. The GSH level in renal tissue of only GEN-treated rats was significantly lower than those in the control group, and administration of PE to GEN-treated rats significantly increased the level of GSH. The group that was given GEN and PE had significantly lower MDA levels in kidney cortex tissue than those given GEN alone. There was no significant difference of NO levels between the groups. In rats treated with GEN + PE, despite the presence of mild tubular degeneration and tubular necrosis is less severe, and glomeruli maintained a better morphology when compared with the GEN-treated group. We think that PE prevents kidney damage by decreasing oxidative stress in kidney.