Background: Nephrotoxicity is an inherent of certain anticancer drugs. Aim: This study aimed to assess the protective effect of onion oil and selenium against cisplatin-induced nephrotoxicity in male rats. Results: Cisplatin (5 mg/kg, i.p.) caused significant increases in serum sodium, blood urea nitrogen, serum creatinine, total sodium and potassium excreted in urine, urine volume and lipid peroxides measured as the malondialdehyde content of kidney, with significant decreases in serum total protein, creatinine clearance, reduced glutathione content of kidney and kidney superoxide dismutase activity as compared to the control group. On the other hand, administration of onion oil (100 mg/kg, p.o.) or selenium (1 mg/kg, p.o.) for 14 days with a single cisplatin dose on the 10^th day ameliorated the cisplatin-induced nephrotoxicity as indicated by the restoration of kidney function and oxidative stress biomarkers. Conclusion: Onion oil and selenium showed protective effects against cisplatin-induced nephrotoxicity.