Magnetic nanoparticles of ZrFe2O5 and Ni0.5Zr0.5Fe2O5 have been synthesized by coprecipitation route. Particle size as estimated by full width half maximum (FWHM) of the strongest x-ray diffraction (XRD)peaks were found in the range of 25-35 ± 4 nm. SEM images reveal that the sample surface exhibit well defined crystalline nanoparticles of spherical shapes with small agglomeration. TEM was used to characterize the microstructure of the samples and particle size determination, which exhibited the formation of spherical nanoparticles.