Resistivity measurements have been made on Nb cavities, as well as on Pb and Cu, at 296, 77, and 4.2 °K by means of a contactless induced‐current method. For superconductors, a constant magnetic field drives the material normal below the transition temperature. These measurements provide a simple means for initial material evaluation as well as a direct means of monitoring the effects of material parameters (purity, heat treatment, gas incorporation, etc.) on the electron mean free path. Approximate determinations ofHc,Hc1, andHc2can also be derived from these measurements. Normal‐state thermal conductivity and the Ginzburg‐Landau parameter &kgr; are calculated from the resistivity measurements.