Apparatus for mixing fuel and an oxidant for use in an autothermal reformer that provides hydrogen to a fuel cell. The apparatus includes a mixing vessel (10), a first inlet (4) to the mixing vessel for movement of gaseous fuel or oxidant therethrough, a second inlet for movement of gaseous fuel or oxidant therethrough, and an exit (60) from the vessel adjacent the autothermal reformer. The discharge ends of the inlets are spaced apart from each other and from the exit which is near a POX reactor (61) that combusts the mixture of fuel and oxidant exiting from the mixing vessel. The first inlet is comprised of a plate (26) with a plurality of tubes (24) extending therefrom through which fuel or oxidant passes. The tubes extend into the mixing vessel and towards the exit of the vessel such that the fuel does not come into contact with the oxidant until the gaseous fuel or oxidant discharges from the ends (30) of the tubes thereby mixing the fuel with the oxidant in the gaseous state prior to passing to the POX reactor.