A micro-structured autothermal reformer was developed for a fuel processing/fuel cell system running on iso-octane and designed for an electrical power output of 5 kW(el). The target application was an automotive auxiliary power unit (APU). The work covered both catalyst and reactor development. In fixed bed screening, nickel and rhodium were identified as the best candidates for autothermal reforming of gasoline. Under higher feed flow rates applied in microchannel testing, a catalyst formulation containing 1 wt.% Rh on alumina prepared by the sol-gel synthesis route proved to be stable at least in the medium term. This catalyst was introduced into the final prototype reactor designed to supply a 5 kW fuel cell, which was based upon micro-structured stainless steel foils. The reactor was optimised for equipartition of flows by numerical simulation. Testing in a pilot scale test rig, which was limited to a specified power equivalent of 3.5 kW(el), revealed more than 97% conversion of gasoline at 124 Ndm(3)/min total flow-rate of reformate, which corresponded to a WHSV of 316.5 Ndm(3)/(h g(cat)). (C) 2007 Elsevier B.V. All rights reserved.