In order to satisfy the needs for electrical power in future combat systems, a gasoline fuel processor (GFP) for an auxiliary power unit (APU) has been developed. This efficient design of a compact hydrogen-production system thermally and physically integrates the unit processes of autothermal reforming, high- and medium-temperature water gas shift, preferential oxidation, heat exchange and external burner into a single hardware package. The start-up strategy is established to turn the GFP on even at subzero temperature and reach the steady-state rapidly. In consideration of both energy consumption and system size, the sequence is initiated from start-burner mode. The catalytic-partial-oxidation (CPO) mode is second, followed by autothermal reforming (ATR). A glow-plug needed to ignite the gasoline is positioned behind the catalyst to minimize soot generation at start-burner mode. In ATR mode, feed rate of water for each heat exchanger is controlled to operate a reactor at target temperature and reduce the water condensation at surface of catalyst. Based on this start-up strategy, a GFP is able to produce a reformate gas that contained >40 vol.% H-2 and <0.5 vol.% CO within 30-35 min at room temperature and -32 degrees C. An APU with a GFP shows the stable start-up and continued operation. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.