The current work presents the synthesis and properties of cerium doped magnetite (Fe3O4) nanoparticles synthesized by standard chemical co-precipitation method using NH4OH as co-precipitating agent. The effects of cerium ion substitution on structural and magnetic properties of magnetite (Fe3O4) nano particles were reported. These materials were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM). The cerium content has a significant influence on structural and magnetic properties. The X-ray diffraction study confirmed the formation of single-phase magnetite with space group Fd3m and crystallite size ranging from 39 to 58 nm. The addition of cerium resulted in a reduction of crystallite size and an increase of cell parameters. FTIR measurements confirmed the formation of different samples and suggested that the reduction of Fe+3 to Fe+2 preferred on a site adjacent to Ce+4. Magnetic measurements revealed that the saturation magnetization (Ms) and remanence (M-r) decreased while the coercivity (H-C) and squareness (M-r/M-s) increased with increasing cerium content. (C) 2015 Elsevier B.V. All rights reserved.