A simulation study of a microreactor for steam reforming of ethanol (ESR) over a washcoated Pd catalyst is reported in the present manuscript. Both co- and countercurrent configurations are considered for the streams of reactants and flue gas through microchannels of a square. section. Two contiguous channels, assumed as representative of the whole reactor behavior, are simulated using a, 1D pseudohomogeneous model. The microreactor performance is analyzed for different heat-supply strategies and channel sizes:The results demonstrate that the ESR in the microreactor is strongly controlled by the heat supply. The hydrogen yield has a marked dependence on the total amount of heat transferred from the flue gas to the reformate and the axial distribution of the heat flow. The cocurrent-flow configuration proved to yield the higher performance. While smaller channels work better for, cocurrent operation, an optimum compromise value is found for the channel size in countercurrent flow.