Experiments were carried out to characterize the kinetics of dimethyl ether (DME) steam reforming (SR) in a fixed bed reactor catalyzed by a bifunctional catalyst comprising a physical mixture of 50:50 wt.% CuO-ZnO-Al2O3-ZrO2 + ZSM-5 at 200-300 degrees C and atmospheric pressure. The influences of the feed composition (steam/DME ratio), temperature and space velocity on DME conversion, hydrogen yield and CO2 selectivity were obtained. A kinetic model for combined DME SR based on the reaction mechanisms for methanol to DME from Park and Froment and methanol SR from Peppley et al. was used. The kinetic parameters were determined by regression using the DME conversion, hydrogen yield and CO2 selectivity at a given steam/DME feed ratio (steam/DME molar ratio of 3.5). (C) 2008 Elsevier B.V. All rights reserved.