A gold nanoparticles (Au NPs)-graphene nanocomposite (Au-graphene nanocomposite) was prepared by electrochemically depositing Au NPs on the surface of graphene sheets, and characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray powder diffraction (XRD), and electrochemical methods. The morphology and size of the Au NPs could be easily controlled by adjusting the electrodeposition time and the concentration of precursor (AuCl4-). The electrocatalytic activities of the nanocomposites toward oxygen reduction and glucose oxidation were investigated by cyclic voltammetry. The results indicated that the nanocomposites had a higher catalytic activity than the Au NPs or graphene alone, indicating the synergistic effect of graphene and Au NPs. Therefore, this study has provided a general route for fabrication of graphene-based noble metal nanomaterials composite, which could be potential utility to fuel cells and bioelectroanalytical chemistry. (C) 2010 Elsevier Ltd. All rights reserved.