Postirradiation electrical resistivity changes have been found to be a measure of the irradiation temperature. Molybdenum and tungsten rod specimens were irradiated in the Experimental Breeder Reactor II to a neutron fluence of 1.1E+26 n/m2 (En > 1 MeV) simultaneously at six different temperatures, ranging from 455 to 1050°C. The postirradiation isochronal resistivity measurements made on the specimens showed a close relationship between the initial resistivity recovery temperatures and the original temperatures determined from the melt wires and SiC monitors irradiated in the same capsules. Experimental results indicated the possibility of molybdenum and tungsten wires as irradiation temperature monitors (molybdenum up to 850°C and tungsten up to ∼1400°C).