In the present study, the effects of spraying conditions on reforming performance were investigated experimentally. Kerosene was used as the liquid fuel for reforming and sprayed by a twin fluid nozzle to facilitate uniform mixing with air and water (steam) at the downstream. The separate effects of the mean drop size of the fuel, the position of the catalytic bed and the air flow rate on the reforming efficiency were analyzed, and the reasons for the results were discussed by examining the temperature distribution inside the reformer and also through visualization of the catalytic bed during the reforming process. The overall reforming efficiency was significantly improved by spraying the fuel because the mixing between the reactants was enhanced. When the distance from the nozzle to the catalytic bed became closer, higher reforming performance was achieved with larger fuel drops due to the more rapid penetration into the catalytic bed with larger momentum. With a larger amount of air supply to the system, fuel reformation was promoted by the high reaction temperature. On the other hand, with the longer distance between the nozzle and the catalytic bed, the poor mixing between the fuel and other reactants (due to the side-wall collision of fuel drops and possible formation of liquid film along the wall) predominated over other effects, and the drop size effect was not accordingly observed. Copyright (C) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.