Introduction. Nephrotoxicity is one of the important side effects of anthracycline antibiotics. The aim of this study was to investigate the effects of nicotinamide (NAD), an antioxidant agent, against nephrotoxicity induced by doxorubicin (DXR). Methods. The rats were divided into control, NAD alone, doxorubicin (20 mg/kg, i.p.) and DXR plus NAD (200 mg/kg, i.p.) groups. At the end of the 10th day, kidney tissues were removed for light microscopy and analysis. The level of tissues' catalase (CAT), glutathione (GSH), glutathione peroxidase (GPx), inducible nitric oxide (iNOS) and endothelial nitric oxide (eNOS) activities were determined. Results. The activities of CAT, GPx, and GSH were decreased, and Po was increased in renal tissue of doxorubicin group compared with other groups. The tissue of the doxorubicin group showed some histopathological changes such as glomerular vacuolization and degeneration, adhesion to Bowman's capsule and thickening and untidiness of tubular and glomerular capillary basement membranes. Histopathological examination showed that NAD prevented partly DXR-induced tubular and glomerular damage. Conclusions. Pretreatment with NAD protected renal tissues against DXR-induced nephrotoxicity. Preventive effects of NAD on these renal lesions may be via its antioxidant and anti-inflammatory action.