A series of Chromium-substituted Zinc ferrites (CrxZn Fe2-xO4  with = 0.00, 0.10, 0.20, 0.30, 0.40) were synthesized via hydrothermal method. The structural characterizations of all the prepared samples were done using XRD, FTIR and EDAX, TEM, HR-TEM and TGA measurements . These studies confirmed the formation of single-phase inverse spinel structure in all the compositions. From HR-TEM measurments, crystallinity are observed to increase with increase of the concentration of Chromium. The surface morphology and particle size of a typical sample were determined using SEM and TEM respectively. The substitution of Chromium strongly influences the magnetic characteristics, and this is confirmed from the magnetization measurements at different temperatures