A study has been made of a contactless technique of measuring resistivity, which uses a time-varying magnetic field to induce eddy currents in a sample and measures the magnetic field produced by the eddy currents. The theoretical basis of this method is studied. An experimental system using a phase discriminating network is developed, and used to measure a voltage induced by the eddy current magnetic field. Data are reported for samples in the range from 0.1 to 11 ohm-cm. This method is predicted to be feasible for measuring resistivities in the range from 10-10 ohm-cm to 10+6 ohm-cm.