This review is focused on discussions about multi-fuel reformer technology for fuel cell vehicles where techniques for onboard hydrogen generation and gas clean-up processes, as well as full considerations and emissions are included. Our conclusion is that the potential for developing a highly efficient, durable and reliable reformer system fur automotive applications is considerably higher if dedicated fuel reformers are used instead of applications where all types of fuels ranging from natural gas to heavy diesel fuels can be used. The authors propose that petroleum-derived fuels should be designed for potential use in mobile fuel cell applications. The present literature review together with site visit discussions has led to the conclusion that there are relatively low emissions from fuel cell engines compared to internal combustion engines. However, the major research work on reformers-fuel cells have been performed during steady-state operation. Emissions during start-up, shutdown and transient operation are basically unknown and must be investigated in more detail. (C) 2001 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.