Ni catalysts supported on ZnxMg1-xAl2O4 spinel oxide have been prepared by the wet impregnation method with 8 wt.% Ni. The samples were characterized by XRD, BET area, TPR, CO2-TPD, SEM-EDX and TPO and tested in the ethanol steam reforming reaction. The XRD patterns of Ni catalysts supported on ZnxMg1-xAl2O4 with x = 1 or 0.5 revealed a highly crystalline spinel phase (ZnAl2O4 type) and different size particles of NiO center dot MgAl2O4 with a poorer crystallinity and NiO were observed for the catalyst supported with x = 0. The presence of Mg into the support composition decreased the Ni2+ reducibility and increased the basicity and the specific surface area, allowing a high dispersion of metallic particles and an improved resistance to carbon deposition in the ethanol steam reforming reaction. Under the experimental conditions used in this work. Ni/MgAl2O4 was the most active catalyst but showed deactivation by graphitic carbon deposition. (C) 2013 Elsevier B.V. All rights reserved.