The aim of this study was to evaluate whether the antioxidant C-phycocyanin (C-PC, 5-30 mg kg(-1) i.p.) was able to prevent cisplatin (CP, 18 mg kg(-1) i.p.) induced nephrotoxicity by reducing oxidative stress in CD-1 mice. Nephrotoxicity was assessed by measuring blood urea nitrogen, plasma glutathione peroxidase, plasma creatinine, the renal activity of N-acetyl-β-d-glucosaminidase, apoptosis and histopathological changes. Oxidative stress was evaluated by measuring the content of glutathione, malondialdehyde, 4-hydroxynonenal and oxidized proteins in renal tissue. C-PC prevented CP-induced renal damage and oxidative stress in a dose-dependent manner. Moreover, C-PC prevented the decrease in the renal activity of the antioxidant enzymes glutathione peroxidase, glutathione reductase, glutathione-S-transferase and catalase induced by cisplatin. In vitro assays showed that C-PC was an effective scavenger of the following reactive species: hypochlorous acid, peroxynitrite anions, peroxyl radicals, diphenyl-1-picrylhydrazyl, hydroxyl radicals, superoxide anions, singlet oxygen and hydrogen peroxide. It is concluded that the protective effect of the nutraceutical C-PC against CP-induced nephrotoxicity was associated with the attenuation of oxidative stress and the preservation of the activity of antioxidant enzymes.