Nickel based ferrites have several applications in microwave components as dense polycrystalline compacts. In this study we have prepared nickel ferrite nanoparticles by a self-ignition reaction directly from a citrate precursor. XRD patterns and FTIR spectra confirm the formation of single phase nickel ferrite. The sample couples readily with microwaves at ambient temperatures and the residual carbon present in the self-ignited sample could be removed in a few minutes by microwave treatment. The samples, however, could not be sintered by microwaves on account of the high sintering temperature of nickel ferrite at which arc formation takes place. (C) 2002 Elsevier Science B.V. All rights reserved.