Gd3+ substituted MnZn ferrites [ Mn0.5Zn0.5GdxFe2−xO4 (x=0.1x=0.1, 0.2, 0.3, 0.4)] nanoparticles have been explored for ferrofluid applications. The oleic acid coated water base ferrofluids of these ferrites are prepared by chemical co-precipitation. The effect of Gd3+ ions on structural morphological and magnetic properties of these samples are characterized by X-ray diffraction, FTIR, EPR and dc magnetization techniques. The crystallite size, particle size and saturation magnetization increases with the increase of Gd3+ ions concentration while lattice parameter and lattice strain reduces. The g-value, peak-to-peak linewidth and spin concentration evaluated from EPR spectra correlated with cations occupancy.