A novel kind of copper-active carbon (Cu-AC) nanocomposites were prepared through copper ions (Cu2+) dipping and hydrogen reducing methods. The Cu2+ ions were reduced by 5% H-2 at 350 degrees C. TEM image indicated that the diameters of copper particles are about 30-60nm. Electrochemical hydrogen storage capacities were determined and the maximum discharge capacities are 319.5mAhg(-1), which is correspondence to the 1.22 wt% of hydrogen deposit values for the 50%Cu-AC1 at room temperature. The hydrogen deposit capacity is stable with less than 5% decrease of the discharge capacity after 20 cycles. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.