BACKGROUND: Gentamicin is widely used broad spectrum aminoglycoside antibiotic. Despite its beneficial effects, gentamicin has considerable nephrotoxic effects. Salicylic acid is a phenolic compound that has anti-inflammatory, analgesic and antipyretic effect. It has also antioxidant activity that can counteract oxidative damages induced by adverse conditions in animals. OBJECTIVES: The work aims to detect the harmful changes in the rat kidney that occur after administration of gentamicin and to determine whether salicylic acid treatment attenuates gentamicin - induced nephrotoxicity. MATERIAL AND METHODS: Fifty healthy adult male Wister albino rats were obtained from the breading animal house, Faculty of Veterinary Medicine, Zagazig University. These animals were divided randomly and equally in to five groups. Each group contains ten rats. Group 1: Included control animals. Group 2: Included salicylic acid-treated animals. Group 3: Included gentamicin-treated animals. Group 4: Included animals treated with salicylic and gentamicin at the same time. Group 5: Included animals treated with gentamicin and remain for recovery. The rats were anesthetized with ether inhalation and sacrificed. The kidneys were removed and processed for light and electron microscopic examination. RESULTS: The histological study revealed that gentamicin causes severe nephrotoxicity. Exposure to gentamicin caused necrosis of tubular epithelial cells. The glomeruli were also affected. On the other hand, salicylic acid administration protected kidney tissue against the nephrotoxic effect caused by gentamicin treatment. Recovery from gentamicin treatment could occur spontaneously but it was slow and incomplete. CONCLUSION: Gentamicin administration leads to harmful changes in the structure of the rat kidney. Spontaneous recovery could occur but it is slow and incomplete. These nephrotoxic changes can be protected by co-therapy with salicylic acid