Magnesium has been deeply studied as a possible hydrogen storage material for both, mobile and static applications. In this work, hydrogen absorption in Ni-catalyzed magnesium was measured in a wide range of pressure (500 kPa-5000 kPa) and temperature (498 K 573 K). Using this information, a model for the absorption kinetics and thermal behavior of the hydrogen storage system was proposed. This model could be used in the design of Ni-catalyzed magnesium storage tanks and other applications. It considers the independent contribution of three variables: temperature, pressure and reacted fraction to estimate the hydrogen absorption rate. An activation energy for the process was estimated and the value obtained (92 kJ/mol) was concordant with previous values reported in the literature. Copyright (c) 2014, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.