Objectives: To explore the protective effects of curcumin against renal injury induced by formaldehyde in rats. Materials and Methods: A total of 21 male Sprague-Dawley rats were included. The animals were divided into three groups. The control group, received 10 ml/kg of physiological saline intragastrically and intraperitoneally on a daily basis. The formaldehyde group were given 10 ml/kg of physiological saline intragastrically plus 10 mg/kg of formaldehyde intraperitoneally. The formaldehyde+curcumin group, received 10 mg/kg of intraperitoneal formaldehyde daily as well as 100 mg/kg of curcumin intragastrically. After the completion of 14 days, the kidneys were removed. Tissue microscopic examination was performed with Hematoxylin-Eosin and Periodic Acid Schiff staining. Also, superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and xanthine oxidase (XO) activities and malondialdehyde (MDA) and nitric oxide (NO) levels were measured in tissue samples. Results: Formaldehyde induced renal injury. The degenerative tissue changes in the formaldehyde+curcumin group seemed to regress, exhibiting similar characteristics to those of the controls. MDA, XO and NO were significantly higher in formaldehyde group than in controls, while a significant reduction occurred in SOD, CAT and GSH-Px activities in the formaldehyde group. Also, renal tissue MDA, XO and NO were significantly lower in the formaldehyde+curcumin group than in the formaldehyde group, while tissue SOD, CAT, and GSH-Px activities were significantly higher. Conclusions: Curcumin improved the formaldehyde-induced renal degeneration. Also, curcumin was found to prevent the reduction in SOD, CAT, and GSH-Px activity, while preventing MDA, XO and NO levels, exhibiting a protective effect against the formaldehyde induced oxidative renal injury.