Magnesium fulleride Mg4C60 was synthesized by a solid state reaction and assigned a rhombohedral structure with a = 9.99 angstrom, alpha = 55.1 degrees from X-ray diffraction measurements. The electrical resistivity measurement of the MgxC60 film showed its non-metallic character. The magnetic susceptibility of Mg4C60 was investigated with ESR and SQUID measurements. From the absence of Pauli paramagnetism in the ESR measurement, Mg4C60 was revealed to behave as a non-magnetic insulator. Large core diamagnetism was detected by SQUID measurements. (C) 2010 Elsevier B.V. All rights reserved.