The effect of Cu-doping on the hydrogen storage properties of Mg(95)Ni(5)Cu(x) (x = 0, 0.5, 1, 2) prepared by hydriding combustion synthesis and mechanical milling (HCS + MM) was studied. For dehydriding properties, the dehydriding temperature onset decreases from 450 K for Mg(95)Ni(5) to 420 K for Mg(95)Ni(5)Cu(2). Additionally, the activation energy for dehydriding decreases from 116 kJ/mol for Mg(95)Ni(5) to 98 kJ/mol for Mg(95)Ni(5)Cu(2), indicating that the dehydriding reaction is activated by the catalytic effect of Cu. Moreover, the hydrogen absorption capacity of Mg(95)Ni(5)Cu(2) at 373 K in 100 s increases from 0.95 to 4.16 wt.% by MM pretreatment before HCS. The factors for the improvement of the hydrogen storage properties are discussed in this paper. (C) 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.