Oxidative steam reforming (OSR) of methanol is shown to produce extremely high hydrogen yield. Specific hydrogen production rates as high as 425 kW(t) per liter of reactor volume were demonstrated in a novel Microlith(R)-based catalytic reactor. At reduced space velocities hydrogen concentration in the reformate stream was as high as 50%, while CO concentration was as low as 1.2%. The thermal efficiency of the OSR process is greater than 80%. It is shown that the autothermal OSR process consists of three reactions-methanol oxidation, methanol decomposition and water gas shift. These reactions have different kinetic rates and progress in an overlapping sequence along the catalyst bed. A radial flow catalyst configuration enables varying gas flow velocity to accommodate the different kinetic rates and heat release characteristics of these reactions. This allows a flat temperature profile and approach to equilibrium product composition to be achieved in a single catalyst bed. (C) 2004 Elsevier B.V. All rights reserved.