This paper analyzes safety aspects inside a Fuel Cell vehicle using Computational Fluid Dynamics (CFD) tools. The research considers an introduction of a leak of hydrogen inside the vehicle, and its dispersion for a set of typical ventilation conditions is analyzed. The leak of hydrogen has been modelled according to the properties of hydrogen and depending on the pressure difference between the hydrogen storage tank (200 bar) and the atmosphere. The parameters considered for the simulations are the flow rate of cabin ventilation air and hydrogen's leak. The results obtained for the hydrogen molar concentration are investigated in different sections of the vehicle. Significant differences between front and rear areas are observed, with higher hydrogen concentrations near the rear ventilation vents. The volume of the vehicle within ignition risk (4-75% hydrogen concentration) is also investigated. Finally, different risk mitigation measures are also proposed. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.