Effects of radiation on thermal and mechanical properties of modified, hydrogenated bisphenol-A type and novolac type epoxy resin based shielding materials have been investigated. The onset temperature of KNS-201 and KNS-301 has been increased with increase in the radiation dose, but that of KNS-501 and KNS-601 has been decreased at radiation dose. Also the thermal stability of shielding material of KNS-601 has been affected less than that of KNS-201 by radiation. At radiation dose up to 0.1 MGy, the tensile strength and flexural strength of the shielding material of KNS-301 and KNS-501 has been increased with increase in the radiation dose. In contrast, that of KNS-201 has been decreased with increase in the radiation dose.