NiZnMg-Ferrite Nano ceramics were prepared by using sol-gel auto combustion method, these ferrites then pelletized and sintered at different temperatures (1000, 1100 and 1200 0 C). Ferrite samples showed spinel structure and inherent properties of high electrical resistivity, low electrical losses and high theoretical densities. Therefore, these ferrites have a potential candidate for high frequency applications. The electrical and structural properties of Ni 0.7-y Zn 0.3 Mg y Fe 2 O 4 (where; y= 0, 0.1, 0.2 and 0.3) were studied and that shows an effect of chemical composition on the electrical, structural, and physical properties depending on Mg content in the Ferrite. Chemical phase analysis carried out by x-ray diffraction spectrum confirms the formation of ferrite Nanopowders with size (22.6 nm), and found that the lattice parameters and particle sizes increase, while theoretical density and porosity decreases with increasing of Mg content in the NiZnMg Ferrites. Resistivity of all samples has been measured at temperatures in the range of (300-540 K), which decreases with increasing of temperatures like a semiconductor behavior.