Acute kidney injury is a frequent disorder that can be mimicked by the application of different nephrotoxic agents, including carbon tetrachloride (CCl₄), where kidney injury marker-1 (KIM-1) has been recognized as a highly specific marker. Melatonin is one of the most powerful natural antioxidants and has numerous beneficial properties. We evaluated the nephroprotective potential of 2 melatonin treatment regimens (pre- and post-intoxication) in a CCl₄-induced acute kidney injury model based on the standard serum parameters, kidney tissue antioxidative capacity, KIM-1 levels, and kidney tissue morphological changes. The two treatment regimens were found to preserve kidney function, as judged from the evaluated standard serum parameters. Only when administered after the intoxication, melatonin preserved total kidney antioxidant capacity; pre-treatment melatonin only preserved reduced glutathione levels. An increase in tissue KIM-1 level was found to be prevented by both treatment regimens, which correlated with the morphological changes seen in the kidney tissues of animals treated with melatonin and CCl₄. The findings of our study are in agreement with the known actions of melatonin in relieving kidney tissue oxidative burden, but also contribute to the understanding of its action by preventing an increase in KIM-1.