This work studied the effect of preparation method of MgO on the performance of Ni/MgO catalysts for steam reforming of ethanol. Three different MgO were prepared by precipitation and aging, precipitation and decomposition of precursor salt. Depending on the synthesis conditions, the basicity and the type of Ni species significantly varied. TPD of adsorbed CO2 showed that the MgO prepared by precipitation and aging possess the highest amount of basic sites. TPR and XANES revealed the presence of two different Ni species: NiO particles and Ni2+ inserted in the lattice of a NiO-MgO solid solution, which is hardly reducible. Ni supported on MgO obtained by precipitation and aging exhibited the highest reduction degree. The preparation method of MgO also affected the amount of carbon formed during SR of ethanol at 773 K under H2O/ethanol molar ratio of 3.0. Increasing basicity decreased the amount of carbon deposits, which was attributed to the increase of carbon gasification rate. (C) 2015 Elsevier B.V. All rights reserved.