A nanocatalyst of CaO supported by Fe3O4 magnetic particles was prepared by a chemical precipitation method. It was characterized by various techniques including X-ray diffraction, transmission electron microscopy (TEM), scanning electron microscopy (SEM); Fourier transforms infrared spectroscopy (FTIR), and Hammett indicator. It has been found that the catalyst consists of CaO and Fe3O4 accom-panied by CaFe2O4. This composite catalyst was used for the catalytic transesterification of palm seed oil. The results revealed that the highest biodiesel yields for palm seed oil of 69.7% can be obtained un-der the conditions of (65 °C reaction temperature, 300 min reaction time, 20 methanol/oil molar ratio, and 10 wt.% of CaO/Fe3O4 catalyst loading). The physicochemical properties of the biodiesel produced from palm seed oil were further studied and compared with the ASTM and the EN biodiesel specifica-tions. The results showed that the properties of the biodiesel produced comply with the international standard specifications. Copyright © 2017 BCREC Group. All rights reserved.