Single phase nanocrystalline Zn 0.8 − x Ni x Mg 0.1 Cu 0.1 Fe 2 O 4 (x=0.0−0.8), were synthesized by sol–gel auto-combustion method without post-preparation treatment and, effect of Ni content on structural and magnetic properties is studied by X-ray diffraction (XRD), magnetic measurements and cation distribution. Scherrer’s grain diameter range between 23.5 and 35.1nm. Experimental and theoretical lattice parameter values suggest that the estimated cation distribution is close to the real distribution. Change in Ni-content leads to variation in cation distribution at site A and B. Ni 2+ ions occupy both A and B site, but when Zn 2+ is fully replaced by Ni 2+ , it totally goes to A site. Both coercivity measured at 50Hz and quasi static coercivity value is found to increase with nickel content. Same trend is observed for anisotropy constant values. Best magnetization value of 25.04emu/g was obtained for the specimen with x=0.60. Variation of magnetic properties and other parameters (obtained via cation distribution) can be understood in terms of observed changes in distribution of cation(s) on A and B site.