[en] Mechanical properties of glass fiber-reinforced plastics (GFRP) irradiated at room temperature with electron beams were studied in order to characterize the radiation resistance. Mechanical properties were tested by flexural strength and interlaminar shear strength (ILSS) at room and low temperature, and flexural fatigue strength at room temperature. The GFRP used in the present study were manufactured trial with three kinds of epoxy matrices having excellent radiation resistance at room temperature and easiness of manufacturing. These composites prepared in selected curing condition were equipped with high flexural strength at low temperature, about two times at room temperature. GFRP composed of 4,4'-tetraglycidyl diamino diphenyl methane cured with 4,4'-diamino diphenyl methane showed the highest radiation resistance: the strength after irradiation up to 90 MGy were kept the initial value, that is, flexural strength of 1000 MPa at 77 K and ILSS of 70 MPa at 123 K. It was also confirmed that the flexural strength measured at 4.2 K were well agreed with the values tested at 77 K. On the effects of fiber-matrix bonding materials by using different kinds and/or amount of silane coupling agents, the pronounced difference were found in the degradation behavior but did not affect to the flexural strength of the GFRP. Flexural fatigue behavior showed rather well radiation degradation comparing with three point bending strength at room temperature. (author)