Hydrogen adsorption properties of some Co-and Zn-based Metal-Organic Framework (MOF) materials were studied at near ambient temperatures. Maximal hydrogen storage capacity of 0.75 wt% was found for a Zn-based material at 175 Bar hydrogen pressure and T = -4 degrees C. Hydrogen adsorption correlated linearly with BET surface area and strongly depends on temperature. Relatively low structural stability of some MOF's results in framework collapse during degassing and hydrogen adsorption measurements. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.