The development of efficient reformers for the on-board-production of hydrogen from liquid hydrocarbon fuels like gasoline is one of the challenges for the implementation of fuel cell propulsion systems for automobiles. It requires detailed kinetic information about the reforming reactions of the main gasoline components. Such information is presently only scarcely available, mainly because of the unusual high temperature and short contact time reaction conditions. Therefore, a novel isothermal reactor for kinetic measurement of heterogeneous catalytic reforming reactions under actual operation conditions (T = 800degreesC, p = 5 bar) has been developed. Different hydrocarbon fuels (iso-octane, hexene, toluene, gasoline) were studied under steam reforming (SR) and autothermal reforming (ATR) conditions using a proprietary noble metal catalyst supported on metallic monolith structures. On the basis of these results different reaction pathways for SR and ATR are discussed. The results obtained will be used for design and optimization of mobile autothermal reformers.