The role of gonadal hormones in the nephrotoxicity of the hepatocarcinogen 2-aminoanthraquinone (2-AAQ) was investigated. Intact and castrated four week old Fischer rats of both sexes and castrated female rats with subcutaneous implants of testosterone propionate pellets were fed 2% 2-AAQ in a Wayne meal diet. After 12 weeks of ad libitum feeding the animals were then given control diet. Based on survival, body, liver and kidney weights, and the histopathological evaluation of the kidneys, castrated female rats given testosterone propionate were afforded the greatest protective effect against the nephrotoxicity of 2-AAQ.