The hydrogen adsorption capacity of different types of carbon nanofibers (Platelet, Fishbone and Ribbon) and amorphous carbon has been measured as a function of pressure and temperature. Results have showed as the more graphitic/ordered carbon materials adsorbed less hydrogen than the more amorphous ones. After that and, with the aim of improve the hydrogen adsorption capacity of these carbon materials, they were functionalizated (oxygen surface groups incorporation) and Ni-modificated. Results also showed an important increase of the H-2 adsorption capacity despite the porosity loss that took place after the treatments. Due to the advantages of functionalization and Ni-modification, both treatments were applied at the same time over the most promising carbon materials from the H-2 adsorption point of view, observing again an improvement of the hydrogen adsorption capacity. Finally, the H-2 adsorption capacity of chemically activated carbon materials increased considerably due the pore structure development and even more if activated materials were Ni-modificated. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.