<div class="htmlview paragraph">Ammonia has a potential as a liquid fuel for fuel cell vehicles, because it can be easily liquefied at a lower pressure and theoretically dissociated to the mixture of high-content hydrogen and nitrogen. Ammonia also has an advantage in terms of global warming because of carbon-free fuel. A fuel cell vehicle system with an ammonia onboard dissociator is proposed in this paper. The effects of temperature, pressure, and space velocity on concentrations of hydrogen and residual ammonia are investigated in the experiment. The residual ammonia separator, necessary even in the optimal condition obtained in the experiment, is designed and prepared. It is demonstrated that the fuel cell vehicle with the ammonia onboard dissociator has the potential as a new concept future vehicle.</div>