Today, it is generally considered as a fact that hydrogen will play a decisive role in a future energy system, when fossil fuels have become scarce and thus expensive and/or unsuitable because of ecological reasons. Moreover, it is likely that hydrogen will be applied first and mainly for transportation at least until an efficient storage of electricity on-board of vehicles is available. Based on the experience of the Industrial Gases Industry and of chemical process engineering, on space technology and new developments, different methods of hydrogen storage have been proposed and partly investigated in the past. An important result is that the most favorable type of fuel tank system depends on the kind of vehicle and the mode of its operation. The paper gives a review of on-board storage methods with examples of applications. Requirements for storage systems with respect to the various means of transportation are discussed, emphasizing ground transport by car and bus and mentioning aviation. Further development is necessary which has to be undertaken now as long as we are not under constraint regarding economy, safety and common acceptance. It is shown that the development of hydrogen technology can benefit the introduction of natural gas powered vehicles, in particular if it is stored as cryogenic liquid. (C) 1998 Published by Elsevier Science Ltd on behalf of the International Association for Hydrogen Energy.