The Co-Fe/Mg/Al catalysts were prepared from the hydrotalcite-like compounds containing Co, Fe, Mg and Al, and applied to the steam gasification of biomass-derived tar. The characterization using TPR, TPO, XRD, Hy adsorption, TEM and EXAFS indicates that the Co-Fe/Mg/Al catalysts have a nanocomposite structure of the Co-Fe bcc alloy particles and the oxide particles of MgAl2O4-based solid solution after the reduction, where Co metal atoms can substitute partially Fe metal sites in bcc Fe metal regarding the Co-Fe bcc alloy particles. The composition of the Co-Fe/Mg/AI catalysts was optimized on the basis of the activity tests. The optimized Co-Fe/Mg/AI catalyst exhibited higher catalytic performance than the reported catalysts such as Co-Fe/a-Al2O3, Co/Mg/AI, Ni-Fe/Mg/Al in terms of activity and resistance to coke deposition. This behavior can be explained by the formation of the Co-Fe bcc alloy nanoparticles with rather uniform composition on MgAl2O4-based solid solution. (C) 2014 Elsevier B.V. All rights reserved.