BACKGROUND Exposure to ionizing radiation (IR) induces severe damage in multiple human tissues. The testes are extremely sensitive to IR, and testes irradiation can result in infertility and abnormality. A novel and safe radioprotector for testes injury from IR is needed. Polydatin (PD) has been proved to have anti-oxidant and anti-inflammatory effects, indicating its potential application in radiation protection. MATERIAL AND METHODS Male wild-type C57BL/6 mice (8 weeks old) were exposed to ionizing radiation. At different times after irradiation, testes were isolated and subjected to hematoxylin-eosin (HE) staining and TUNEL staining, as well as related quantification. ELISA assay was used to measure the level of inflammatory cytokines, and apoptosis proteins were detected by Western blot assay. Intracellular ROS was measured by DCFH-DA flow cytometry method. RESULTS In the present study, we demonstrated that polydatin effectively alleviated testes injury and retained sperm viability. PD pretreatment also inhibited cell apoptosis caused by irradiation. Radiation-induced decrease of FSH and testosterone was also inhibited by PD treatment. Finally, we showed that PD obviously reduced the ROS level, using DCFH-DA method. We also found that PD reduced the concentration of the oxidative products MDA and 8-OHdG. PD also inhibited apoptosis-related proteins such as Bax and caspase 3. CONCLUSIONS Our data proved that polydatin effectively alleviated testes injury after irradiation, mainly through reducing ROS and oxidative stress. Our findings suggest polydatin as a potential radioprotector for testes radiation damage.