Microchannels were patterned on the metal sheets and fabricated to make a reformer and vaporizer unit. Three types of patterned sheets were prepared to construct a base structure. The aspect ratio of microchannels can be regulated by changing the number of microchannel sheets. Catalyst was deposited inside the microchannel of a reformer unit. Electric heaters provide heat for the endothermic reaction and the vaporization of liquid fuel. A vaporizer and a reformer unit were connected serially to make a proto-type microreactor. The dimensions of the reformer and vaporizer unit excluding fittings were about 70 mm x 40 mm x 30 mm, respectively. The steam reforming of methanol was conducted with the microreactor. The performance of the microreactor was investigated at various operating conditions. The developed fuel processor generates enough hydrogen for power output of 15 We. (C) 2004 Elsevier B.V. All rights reserved.