Herein we report a facile approach for synthesis of well dispersed hydrated ruthenium oxide nanoparticles onto the surface of hydrogen exfoliated graphene (HEG) sheets via hydrothermal synthesis route. The as prepared hybrid nanocomposite (RuO 2·xH 2O/HEG) was characterized by X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM). A symmetrical supercapacitor was fabricated and the electrochemical performance of this model supercapacitor cell was investigated by cyclic voltammetry (CV), chronopotentiometry (CP) and impedance spectroscopy (EIS) in 1.0 M H 2SO 4 solution. The hybrid nanocomposite shows a maximum specific capacitance of 154 F/g and energy density of about 11Wh/kg at a specific discharge current of 1 A/g (20 wt% Ru loading). The composite also shows a maximum power density of 5 kW/kg and coulombic efficiency of 97% for a specific discharge current of 10 A/g. © 2011 IEEE.