Methane reforming with carbon dioxide to synthesis gas was investigated over a series of Ni/HY catalysts promoted by Mg, Mn, K, and Ca. These catalysts were characterized by XRD, BET, FT-IR, and TGA analyses before and after the reaction. It was observed that Ni-Mg/HY catalyst showed the highest carbon resistance and the most stable catalytic performance. It was also revealed that the addition of Mg promoter reduced the size of nickel species and produced the highly dispersed nickel species, and consequently, retarded the catalyst deactivation. The reactive carbonate species formed on the magnesium oxide in the Ni-Mg/HY catalyst played an important role in suppressing carbon deposition on the catalyst surface. (c) 2005 Elsevier B.V All rights reserved.