The electrical resistivity of a Hf filament containing 4.9 at. % Zr was measured in the temperature interval from 1155° to 2250°K. The resistivity increases from 37 &mgr;&OHgr;‐cm at room‐temperature to 187 &mgr;&OHgr;‐cm at 2025°K where the alloy undergoes a transition from an hcp to a bcc structure with a corresponding decrease in resistivity to 173 &mgr;&OHgr;‐cm. From data in the literature the transition temperature of pure Hf is estimated to be 2030°±30°K. Graphs of total emissivity versus temperature indicate that changes in the surface characteristics of the sample occurred during the measurements. After surface conditions became constant, the total hemispherical emissivity increased linearly with temperature from about 0.26 at 1200°K to 0.31 at 2000°K.