Chromium doped Ni-Cu-Zn nano ferrites with chemical formula Ni 0.2 Cu 0.2 Zn 0.6 Fe 2-x Cr x O 4 (x = 0.0, 0.2, 0.4, 0.6, 0.8, and 1.0) were prepared by using sol-gel auto combustion method. The prepared precursors of Chromium substituted Ni-CuZn ferrites were sintered at 500 °C for 4h. Compositional stoichiometry were confirmed from EDAX patterns. The XRD data revealed that the all samples possess a single phase cubic spinel structure. The Lattice constant, X-ray density, hopping lengths and crystallite size determined from XRD data decreases with increase in Cr 3+ concentration. The IR spectra show two major absorption bands, high frequency band ν 1 ≈ 600 cm -1 and low frequency band ν 2 ≈ 450 cm -1 attributed to the stretching vibration of tetrahedral and octahedral sites respectively. The surface morphology of the prepared samples was studied by Scanning Electron Microscopy and Transmission Electron Morphology.