Polyethylene glycol (PEG) coated Zn0.3Fe2.7O4 magnetic nanoparticles in the presence of Fe2O3 phase were synthesized by citric acid-assisted hydrothermal reduction process. The characteristics of coated and non-coated Zn0.3Fe2.7O4 nanoparticles were examined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM) and specific loss power (SLP) measurements. PEG was successfully coated on the surface of the nanoparticles through chemical interaction as analyzed using FTIR. The results confirmed that there were no significant differences in the SLP measurements of coated (17.62 W/g) and non-coated (18.7 W/g) nanoparticles. MTS assay was utilized to evaluate the cell cytotoxicity of the nanoparticles using MCF7 cell lines. Cell data indicated that the synthesized nanoparticles were non-toxic, making them a good candidate for biomedical applications. (C) 2018 Elsevier B.V. All rights reserved.