Ethanol steam reforming over a Co/Al2O3 catalyst was studied theoretically in a catalytic Pd-Ag membrane reactor (CMR). A mathematical model has been developed to elucidate the behavior of CMR by taking into account the chemical reactions, heat and mass transfer phenomena. The effect of operating parameters on the performance of CMR has been evaluated in terms of ethanol conversion, hydrogen recovery and hydrogen yield. The results revealed the high performance of this configuration is related to the continuous removal of hydrogen from the retentate side, shifting the reaction equilibrium towards hydrogen formation. Sensitivity analysis of operating parameters indicate that ethanol conversion is favored at higher temperatures, pressures, sweep ratios and feed molar ratios. Moreover, increasing the feed molar ratio enhances the ethanol conversion, and decreases the hydrogen recovery due to reduction of partial pressure of hydrogen and consequently decreasing the driving force for the hydrogen permeation through the membrane. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.