Series of single-phase Ni1-xZnxFe2O4 (x = 0.20, 0.35, 0.50 and 0.60) nanopowders with average particle size of similar to 35 nm have been synthesized by using oxalate based precursor method. Precursor powders were synthesized by reacting aqueous solutions of metal nitrates and oxalic acid by using different total metal ions: oxalic acid molar ratios and then evaporating them to dryness. Pure, single-phase Ni-Zn ferrite nanopowder was formed by calcining the precursor with total metal ion: oxalic acid ratio of 1:0.125 at a temperature of 850 degrees C. The synthesized nanopowders were characterized by using X-ray diffraction, Thermogravimetric and Differential Scanning Calorimetric analysis, Transmission Electron Microscope and Scanning Electron Microscope. Room temperature DC resistivity of the nanopowders was measured with respect to temperature by the two-probe method and was of the order of similar to 10(7) Omega cm. Room temperature saturation magnetization was measured by using Vibrating Sample Magnetometer and it varied between 34-49 emu/g depending on the composition. This aqueous solution based method provides a simple and cost-effective route to synthesize single phase, Ni-Zn ferrite nanopowders. (C) 2010 Elsevier B.V. All rights reserved.