Rh(1%)@CexZr1-xO2-Al2O3 nanocomposites have been investigated as active and thermally stable catalysts for ethanol steam reforming. Preformed Rh nanoparticles have been efficiently protected from deactivation/sintering by a porous layer of nanocomposite oxides. Chemisorption and activity data confirm the good accessibility of the metal phase to the reaction mixture. No appreciable deactivation is observed after 160 h of reaction at 873 K. The ceria-zirconia mixed oxides favour reforming reactions, reduce coke formation and facilitate its removal. The alumina component is important to stabilize the ceria-zirconia mixed oxides, preventing their sintering. (C) 2006 Elsevier B.V. All rights reserved.