Various supported Ni catalysts have been applied for combined steam and carbon dioxide reforming of methane to produce synthesis gas (H-2/CO = 2). Highly active and stable nano-sized Ni/Mgo-Al2O3 catalyst has been successfully developed for the target reaction. The high activity and stability is due to beneficial effects of MgO such as enhanced steam adsorption, basic property, nano-sized NiO crystallite size and strong interaction between Ni and support.