The protective effect of quercetin on cisplatin-induced renal and testicular tissue damage was investigated using biochemical, histopathological and histological approaches. A total of 40 male rats were divided into 5 groups as follows: control; cisplatin alone; quercetin alone; cisplatin+quercetin; and quercetin+cisplatin. Cisplatin was administered to rats at a single dose of 7mgkg(-1) intraperitoneal. Quercetin was administered by gavage daily for 10days at dosage 50mgkg(-1). At the end of the study serum, total antioxidant capacity (TAC) levels and total oxidant status (TOS) were determined. Malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and xanthine oxidase (XO) were studied separately in serum, renal tissue and testicular tissue. Renal and testicular morphological alterations were assessed, histopathologically. Epididymal sperm concentration, motility and morphology were investigated. Testicular and renal TAC and TOS values did not alter significantly. Renal CAT levels were increased by cisplatin and cisplatin plus quercetin groups that is reversed by administration of quercetin before cisplatin. MDA, CAT, SOD ve XO levels of testicular tissue did not differ significantly. Cisplatin and cisplatin plus quercetin groups had decreased sperm motility ratio and increased abnormal spermatozoa. Quercetin partially reverses some of the cisplatin-related pathological effects on kidney and testis.