Cisplatin is a chemotherapeutic agent widely used in treatment of several cancers. It is documented as a major cause of clinical nephrotoxicity and hepatotoxicity. The purpose of this study was to investigate the involvement of oxidative stress in the pathogenesis of cisplatin-induced liver and kidney injury. Wistar rats were divided into four groups. Group 1 (control) was intraperitoneally (IP) injected with a single dose of 0.85% normal saline. Groups 2, 3 and 4 were IP injected with single doses of cisplatin at 10, 25 and 50 mg/kg body weight (BW), respectively. At 24, 48, 72, 96 and 120 h after injection, BW, levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), creatinine, malondialdehyde (MDA), and activity of superoxide dismutase (SOD) and histology of the liver and kidney were evaluated. Cisplatin caused a reduction in BW of rats in groups 2, 3 and 4 at all post injection intervals. The levels of serum ALT, AST, BUN and creatinine and MDA of the kidney and liver were markedly increased especially at 48 and 72 h, whereas the activity of SOD was decreased after cisplatin injection. Liver sections revealed moderate to severe congestion with dilation of the hepatic artery, portal vein and bile duct and disorganization of hepatic cords at 50 mg/kg of cisplatin. Kidney sections illustrated mild to moderate tubular necrosis at 25 and 50 mg/kg of cisplatin. Therefore, oxidative stress was implicated in the pathogenesis of liver and kidney injury causing biochemical and histological alterations.