The aim of this study was to investigate the effects of royal jelly against gamma-radiation induced oxidative damage in liver and lung tissue after total body irradiation. The adult male Sprague Dawley rats were randomly divided into six groups of sixteen animals each; group 1: control group (C), group 2: only irradiated rats (IR), group 3: irradiated rats with royal jelly administration at 25 mg/kg/day (IR+RJ25), group 4: irradiated rats with royal jelly administration at 50 mg/kg/day (IR+RJ50), group 5: only royal jelly administration at 25 mg/kg/day (RJ25), group 6: only royal jelly administration at 50 mg/kg/day (RJ50). Royal jelly (RJ) was administered at a dose of 25 and 50-mg/kg body weight, by gavage for 10 days prior to irradiation and 10 days after irradiation. On the tenth day of study, radiotherapy was applied to the whole-body by single fraction at a dose of 6 Gy. Half of rats were sacrificed at 24 hours and 10 days after irradiation under ether anesthesia. Blood samples were collected and analysed for alanine aminotransferase, aspartate aminotransferase, triygliceride, total cholesterol and gamma glutamyl transpeptidase levels. The lung and liver samples were stored for the measurement of malondialdehyde, glutathione peroxidase, superoxide dismutase and catalase activities. Rats exposed to whole-body irradiation induced a marked liver failure, characterized with a significant increase in serum AST, ALT, cholesterol and triglyceride concentrations, and also they had higher lung and liver MDA and lower GSH-Px, CAT and SOD (p<0.001). Administration of royal jelly resulted in a significant decreased in oxidative stress parameters and biochemical parameters, and certainly increased antioxidant activities. Furthermore, pre- and post-treatment with RJ was more effective than pre-treatment with RJ.