Al2O3 SUBSTITUTED nickel zinc nano-ferrite Alx Ni0.5-x Zn0.5 Fe2O4 (x = 0.0, 0.1, 0.2, 0.3) was prepared by the citrate sol-gel methodusing nickel, zinc, iron and aluminum nitratesand sintered at 800oC for 3 h in air. Prepared nano-sized ferrites were characterized by X-ray diffraction, High resolution transmission and scanning electron microscopy and Fourier transforms infrared spectroscopy. The estimated crystallite sizes were in the range of 24.7–32.9 nm. HR-TEM data appears that all nano-ferrite samples are composed of more or less agglomerated nanoparticles with the average particle size of nanocrystallites is ~31 nm. The impact of introducing Al ions by Ni on themagnetic properties of the prepared nano-ferrite was investigated utilizing magnetic measurements at room temperature. The changing of crystallite sizes, lattice parameter and the surface area with increasing the Al content were determined.The saturation magnetization (Ms) and coercivity (Hc) values vary from 47.894-32.314 and 70.37-60.117 G; respectively.