In the present work, Cu-Ni supported catalysts were tested in ethanol steam reforming reaction. Two commercial amorphous solids (SiO2 and gamma-Al2O3) and three synthesized materials (MCM-41, SBA-15 and ZSM-5 nanocrystalline) were used as support. A series of Cu-Ni/SiO2 catalysts with different Cu and Ni content were also prepared. It was found that aluminium containing supports favour ethanol dehydration to ethylene in the acid sites, which in turn, promotes the coke deactivation process. The highest hydrogen selectivity is achieved with the Cu-Ni/SBA-15 catalyst, due to a smaller metallic crystallite size. Nevertheless, the Cu-Ni/SiO2 catalyst showed the best catalytic performance, since a better equilibrium between high hydrogen selectivity and CO2/COx ratio is obtained. It was seen that nickel is the phase responsible for hydrogen production in a greater grade, although both CO production and coke deposition are decreased when copper is added to the catalyst. (C) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.