Abstract We report here a theoretical investigation of molecular hydrogen storage on [Pb2(TETA)]·6H2O. Because of their high surface areas, Pb-based MOFs are promising hydrogen storage systems. Ab-initio calculations using density functional theory at the PBE level have been performed to explore the most energetically favorable adsorption sites, and to determine the nature of hydrogen bonding and the storage capacity. Our results show clearly that a hydrogen molecule can be adsorbed on different sites of the MOF with high adsorption energies per site of over 10 kJ/mol. [Pb2(TETA)]·6H2O exhibits significant elastic properties enabling it to store up to 21 molecules per unit cell. Furthermore, analysis of the nature of the bonding shows that these molecules are physisorbed on the surface, and, therefore, can be readily desorbed for use as fuel.