With the ITER in operation, one of the factors determining the life time of high-heat flux components, such as the divertor and first wall, will be the materials resistance to cyclic loading. The report presents the results of an investigation of low cycle fatigue (LCF) of GlidCopAl25IG (CR+ann) alloy and GlidCopAl25IG (HIP) from GlidCopAl25IG/316LN HIP joints in the unirradiated state and after neutron irradiation up to 0.4 dpa at T i r r =150 or 300 o C. Testing of base alloy specimens irradiated at 150 o C demonstrates that on the whole the number of cycles to fracture is decreased. When tested at 300 o C, the specimens irradiated at 300 o C up to 0.4 dpa demonstrate a slight increase in the number of cycles to fracture as compared with the unirradiated ones.