Methanol decomposition to carbon monoxide in a palladium membrane reactor (PMR) is presented, where a 1 wt % Pd/SiO2 catalyst and a Pd91Ru6In3 alloy membrane tube were employed. Experiments were carried out at relatively low temperatures, 220-250 degrees C, in a PMR mode as well as a conventional catalytic reactor (CCR) mode. A kinetic analysis for methanol conversion change in the CCR mode revealed that the overall reaction rate was controlled by the desorption process of the resultant carbon monoxide from the active sites of the catalyst surface. In the PMR mode it was shown that the selective separation of produced hydrogen from the reaction to the permeate side led to an increase in methanol conversion. Further, amounts of byproducts such as carbon dioxide, dimethyl ether, and methyl, formate were found to be also influenced by the hydrogen separation.