Abstract: This study aims at investigating the effect of pre-treatment, co-treatment and post-treatment with Allium cepa extract, AcE, on cadmium-induced renal toxicity and confirming possible mechanisms by which Allium cepa extract reduce/restore cadmium induces nephrotoxicity. Thirty male Sprague Dawley rats were used. They were divided into 5 groups (n = 6). Group 1 was used as control. Group 2 was intraperitoneally administered 1.5 mL kg-1 BW of 0.3 mg L-1 of cadmium sulphate for 3 days. Group 3 was pretreated with 1.0 mL kg-1 BW of AcE for 8 weeks followed by intraperitoneal administration of 1.5 mL kg-1 b.wt. of 0.3 mg L-1 of cadmium sulphate. Group 4 was co-treated with 1.5 mL kg-1 BW of 0.3 mg L-1 of cadmium sulphate for 3 days and 1.0 mL kg-1 BW of AcE for 8 weeks simultaneously. Group 5 was post-treated with 1.0 mL kg-1 BW of cadmium sulphate for 8 weeks following a 3 day course of 1.5 mL kg-1 BW of 0.3 mg L-1 of cadmium sulphate intraperitoneal administration. All groups were allowed free access to standard rat chow and water throughout the period of experiment. After the experiment period, rats were sacrificed by cervical dislocation and blood sample were obtained via cardiac puncture. The kidneys were also excised. Changes in body and kidney weights were determined. Renal weight index, 24 h urine volume, renal clearance and lipid peroxidation status were also determined. There was no significant change in body and kidney weight and renal weight index in all groups. Renal clearance and 24 h urine volume were significantly reduced in group 2 rats when compared to all groups. Renal clearance was also reduced in group 3 and 5, though this decrease was only significant when compared with the control group. Plasma and tissue SOD activities were significantly increased in group 2. Plasma and tissue MDA levels were significantly increased in group 2, 3 and 5. This study shows that cadmium induces nephrotoxicity by impairing renal functions and stimulating lipid peroxidation. Pre-treatment and post-treatment of AcE in cadmium-treated rats produced mild protective potentials. However, co-treatment with AcE during cadmium administration showed significant antioxidative potentials in preventing cadmium-induced nephrotoxicity.