The present work deals with the synthesis of nickel ferrite/SiO2 nanocomposites, obtained by embedding nickel ferrite nanoparticles in a silica matrix, through sol-gel method based on hydrolysis and condensation of a silicon alkoxide and thermal treatment. Methods employed in characterization of the materials obtained at different ferrite concentration and at suitable thermal treatments were differential scanning calorimetry (DSC), X-ray diffraction (XRD), mid-infrared (IR) spectra and transmission electron microscopy (TEM). In purpose to evaluate magnetic properties of these nanocomposites, static magnetic measurements using vibrating sample magnetometer (VSM) were carried out. (C) 2004 Elsevier Ltd. All rights reserved.