Hydrogen is one of the best alternative to petroleum as an energy carrier. However, the development of a Hydrogen-based economy requires commercialization of safe and cost-effective Hydrogen storage system. In this paper, alloys belonging to Mg-Zr-Mn-Ni alloy system are synthesized using high energy ball milling method. The particle size evolution, chemical analysis and nano-scaled structures were characterized by using SEM, EDXS and XRD techniques, respectively. The optimized - highest hydrogen storing - alloy has particle size of about 8.36 +/- 1.17 gm with crystallite size 16.99 +/- 5.48 nm. Hydrogen absorption-desorption measurement is carried out on the principle of pressure reduction method. The alloy coded with MZ1 shows uptake of greater than 7 mass % H-2 at a charging temperature of 200 degrees C, indicating high gravimetric hydrogen storage capacity at relatively lower hydriding temperature. The optimized Mg-Zr-Mn-Ni alloy also shows considerably enhanced hydriding - dehydriding kinetics, compare to pure Mg. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.