Ni, Fe2O3, and CNT were added to Mg. The content of the additives was about 20 wt % with that of Fe2O3 6 wt%. The contents of about 20 wt % additives and 6 wt% Fe2O3 are known optimum ones to improve the reaction rates of Mg with H-2. Samples with compositions of 80 wt% Mg-14 wt% Ni-6 wt% Fe2O3 (named as Mg-14Ni-6Fe(2)O(3)), and 78 wt% Mg-14 wt% Ni-6 wt% Fe2O3-2 wt% CNT (named as Mg-14Ni-6Fe(2)O(3)-2CNT) were prepared by reactive mechanical grinding. The hydriding and dehydriding properties of these samples were then measured, and the effects of Ni, Fe2O3, and CNT addition on the hydriding and dehydriding rates of Mg-based alloys were investigated by comparing their hydrogen-storage properties with those of pure Mg and Mg-10 wt% Fe2O3. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.