Physisorption of molecular hydrogen on pristine single-walled carbon nanotube and three types of topologically defected nanotubes (Stone-Wales, vacancy and interstitial defects) at different temperatures 77, 300 and 600 K has been investigated via molecular dynamics simulation. The interatomic interactions (covalent bonds) between the carbon atoms within the nanotube wall were modeled by the well-known bond order Tersoff potential. The applied intermolecular forces are modeled using the modified form of the well-known Lennard-Jones potential based on the nanotube curvature. The adsorption/desorption cycle was followed by increasing the operating temperature under the pressure of 1 bar. The simulation results of exposing 6.5%wt of H-2 on defected and pristine (3,3) nanotubes reveal that the highest and lowest adsorption energies and storage capacities are obtained from the nanotubes with interstitial and vacancy defects, respectively. Copyright (C) 2010, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.