Mg-23.5wt%Ni-10wt%Cu and Mg-23.5wt%Ni-10wt%La alloys were prepared by melt spinning and crystallization heat-treatment. The Mg-23.5Ni-10Cu alloy (5.18 wt%) after planetary ball milling has a higher hydrogen-storage capacity than the Mg-23.5Ni-10La alloy (4.98 wt%) at 573 K. The activated Mg-23.5M-10Cu alloy has a slightly lower hydriding rate in the beginning, but a higher hydriding rate after about 5 min than the activated Mg-23.5Ni-10La alloy at 573 K. The activated Mg-23.5Ni-10Cu alloy has a much higher dehydriding rate and a larger quantity of the decomposed hydrogen than the activated Mg-23.5Ni-10La alloy at 573 K. (C) 2007 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.