Microchannel methanol steam reformer was developed as compact hydrogen supplier for small fuel cells. Two types of reactors comprising fuel vaporizer, heat exchanger, catalytic combustor and steam reformer were integrated and their hydrogen production performance was evaluated. Each basic unit reactor consists of microchannel patterned stainless sheets. Methanol steam reformer was fabricated by coating a commercially available Cu/ZnO/Al2O3 catalyst inside the microchannel reactor. Pt/Al2O3 pellets prepared by incipient wetness method were filled in the cavities of the catalytic combustor. The prepared unit reactors were integrated to have independent two flow paths including catalytic combustor and methanol steam reformer for the supply of reaction heat and for the production of hydrogen, respectively. The comparison of two types of integrated reactors revealed that the fabrication process of reactor such as microchannel patterning, catalyst coating and microchannel bonding can significantly affect the reactor performance. In this work, the superior fuel processor, which has the dimensions of 60 turn x 40 turn x 30 turn, produced 450 ml/min dry reformate including 73.3% H-2, 24.5% CO2 and 2.2% CO at 250 degrees C which can produce power output of 59 W. (c) 2005 Elsevier B.V. All rights reserved.