We elucidate the effect of Fe addition on the phase transformation and the diffusion of hydrogen in the V-H system. V forms monohydride (beta) and dihydride (gamma) phases by hydrogenation. The gamma phase of VH2 has a face centered cubic (FCC) structure but V1-xFex. (0.03 <= x <= 0.10) forms the FCC hydride phase though the hydrogen content is less than half of VH2, resulting in decreasing the hydrogen storage capacity. On the other hand, for the beta phase proton nuclear magnetic resonance (H-1 NMR) demonstrates that addition of Fe increases the density of states at the Fermi energy N(E-F) and the activation energy for hydrogen diffusion E-H. This indicates that Fe has the effects of stabilizing the hydride phase and of suppressing the diffusion of hydrogen in the V-H system. Copyright (C) 2016, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.