Fuel cell vehicles are currently undergoing extensive research and development due to their potential for low emissions and high efficiency. Fuel cells are rapidly appearing not only in on-road vehicles but also in off-road vehicles. Off-road vehicles require special geometrical and performance parameters to be able to work in different road conditions. Gradability is one of the most important parameters in off-road vehicle performance which is defined as vehicle's ability to climb a grade at a given speed. This paper presents a comparison study between four-wheel drive (4WD) fuel cell hybrid electric vehicle gradability performance and internal-combustion engine (ICE) 4WD vehicle using Matlab/Simulink software. (C) 2012 Elsevier B.V. All rights reserved.