One-step synthesis of carbon-encapsulated Fe(3)O(4) core/shell composites is reported. The Fe(3)O(4) cores were formed via the reduction of Fe(3+) by glucose under alkaline conditions obtained by the decomposition of urea. The amorphous carbon shells were carbonized from glucose. A possible formation mechanism for the Fe(3)O(4)@C composite was discussed. In order to characterize these Fe(3)O(4)@C core-shell composites, high-resolution transmission electron microscopy (HR-TEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), x-ray photoelectron spectroscopy (XPS) and a superconducting quantum interference device (SQUID) magnetometer were employed to characterize the sample obtained using the above method.