In this paper, the structure, hydrogen storage performance, electrochemical discharge and cyclic characteristics of La0.7Mg0.3Ni3.2Co0.35-xCux alloys were investigated using X-ray diffraction (XRD), pressure composition isotherm (PCT) and electrochemical tests. XRD tests showed that all of the alloys were composed of La2Ni7 and LaNi phases. The ratio of LaNi phase in these alloys increased with increasing substitution of Cu for Co. PCT tests showed that increasing substitution of Cu for Co resulted in the decrease of hydrogen storage capacity and the increase of plateau pressure. Electrochemical discharge tests showed that the discharge capacity increased first and then decreased with increasing substitution of Cu for Co. (C) 2010 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.