Ultrafine Ni0.8Zn0.2Fe2O4 particles dispersed in silica (SiO2) matrix are produced by sol-gel method. The powders were subjected to X-ray diffraction to confirm the formation of crystalline phases. The physical properties such as bulk density, true density, % of porosity and % of linear shrinkage were studied. The magnetic permeability as the function of frequency from 1 kHz to 13 MHz and temperatures from room temperature to 300degreesC were studied for samples sintered at temperature 1250degreesC. The AC electrical resistivity as the function of frequency and DC electrical resistivity as the function of temperature were studied. The AC-resistivity of the order of greater than or equal to 10(5) Omegacm and DC-resistivity greater than or equal to 10(8) Omegacm were obtained at room temperature. Microstructural features of sintered samples show the presence of ferrite grains of 1 - 2 mum size. (C) 2004 Kluwer Academic Publishers.