An auto-combustion method was used to prepare manganese substituted nickel and zinc ferrites under three different fuel ratios (50%, 75% and 100%). The powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and energy dispersive X-ray spectrum (EDX). The combustion reaction time of 50% fuel ratio is longer than the other ratios (75% and 100%). The smallest range of particles of about 12 to 33nm for Mn–Zn ferrites and 20–60nm for Mn–Ni ferrites were achieved only at 50% fuel ratio. The external morphology of the samples is visualized through SEM. The microstructure and particle size of the annealed sample were analyzed by TEM. The composition of the elements presence in the samples was determined by EDX spectrum. Also, the magnetic behavior of the samples annealed at 600°C and 900°C was investigated by using a vibrating sample magnetometer (VSM).