In this work a comparison between methanol steam reforming (MSR) reaction and ethanol steam reforming (ESR) reaction to produce hydrogen in membrane reactors (MRs) is discussed from an experimental point of view. Both reaction systems have been investigated by considering the influence of the membrane characteristics as well as the influence of the operating temperature. In the case of a dense membrane, the sweep gas flow rate and the different flux configurations have also been analysed. Experimental results, in terms of reactant conversions as well as hydrogen production and gases selectivity in MRs and in a traditional reactor (TR). are presented. Catalyst stability in both reaction systems has also been tested. (c) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.