Microreactors have important advantages due to the increased heat and mass transfer resulting from the small dimensions of the system. This results in enhanced performance and efficiency. Microreformers with wall-coated or suspended catalytic layer configurations have been studied due to their lower transport resistances compared to packed-bed microreformers. In the present work, a theoretical study of the reacting flow in a wall-coated microreformer is carried out. The theoretical results for the conversions and carbon monoxide concentration of wall-coated reformers are compared with the reported experimental data. The effects of important parameters for wall-coated reformers such as the catalyst layer thickness, wall temperature, and the flow velocity of the reactants are studied. Recommendations for the design of micro wall-coated reformers are provided. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.