The electrical properties of polycrystalline NiZn ferrite, Zn 0.44 Ni 0.38 Fe 2.18 O 4 , were investigated by impedance spectroscopy over the frequency and temperature ranges, 5 Hz to 2 MHz and 10 to 600 K and by magnetic permeability measurements at room temperature. Samples were sintered in either conventional or solar furnaces followed by quenching or slow cooling to ambient temperature. Depending on processing conditions, the room temperature electrical resistivity of conventionally-sintered samples varied by seven orders of magnitude, from 5 ohm cm for a sample Samples sintered in the solar furnace were much more conductive than ones that were slowcooled after conventional sintering and this is attributed to the relatively rapid cooling rate after exposure in the solar furnace, which preserved some of the oxygen deficiency present at high temperature. For the same reason, samples that were slow cooled in N 2 were also much more conductive. For conventionally-sintered samples of similar density, quenched samples had much higher imaginary permeability, attributed to their lower resistivity and higher eddy currents, than slow-cooled samples. Solar-sintered samples had higher real permeability than slow-cooled, conventionally-sintered ones mainly due to a combination of their lower resistivity and higher density, 96% compared to 86%.