Nickel catalysts supported on silica-zirconia mixed oxides were prepared by homogeneous precipitation in sol-gel-derived wet silica gel. Their structural properties and catalytic performance in steam-reforming of methane were investigated from the viewpoint of steam resistance. Ni/SiO2 without zirconia readily loses its catalytic activity during the reaction because the coarsening of silica that occurs in the presence of high-temperature steam hinders the active surface of Ni. The addition of zirconia drastically increases the steam resistance of silica. Ni/SiO2-ZrO2 catalyst shows steady activity in steam-reforming of methane without any changes in pore structure. (C) 2004 Elsevier B.V. All rights reserved.