Exposure to carbon tetrachloride (CCl 4 ) induces acute and chronic renal injuries as well as oxidative stress in rats. The aim of this study was to evaluate the effect of exogenous melatonin (MEL) treatment on CCl 4 -induced oxidative stress and nephrotoxicity in rats using histopathological and biochemical parameters. Serum creatinine, blood urea nitrogen (BUN), nitrite and albumin concentrations were measured for the evaluation of renal function. Antioxidant status in the kidney tissue was estimated by determining the activities of superoxide dismustase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) and glutathione-S-transferase (GST) as well as thiobarbituric acid reactive substances (TBARS) and reduced glutathione (GSH