The NiCoFerrite nanoparticle has been prepared using thermal method. Polyvinyl pyrrolidon (PVP) was used as a reducing agent due to its reducing effect on agglomeration of particles. The characterization studies such as X-ray diffraction (XRD) and transmission electron microscopy (TEM) have been done for explore the particles size. By Scherer‘s equation the average particles size has been estimated that support TEM results. An increasing in particles size was observed with increasing calcinations temperature. FTIR confirmed the presence of metal oxide.