Nanostructured Au/Al2O3-CeO2 catalysts with a low content of precious metal (0.9% wt.) were prepared immobilizing two different stabilized Au sols on a high surface area Al2O3-CeO2 mixed oxide with a uniform pore size distribution, synthesized by a one-pot methodology. The samples were characterized by elemental analysis. N-2 physisorption, XRPD. TEM and Al-27-MAS NMR techniques. The catalytic activity of the two samples in the preferential oxidation of CO in excess of H-2 (CO-PROX) was comparatively evaluated in the 35-110 degrees C temperature range. The Au-THPS/AlCe2O sample, prepared immobilizing a sol obtained reducing an aqueous solution of gold tetrachloroaurate salt with bis[tetrakis(hydroxymethyl)phosphonium sulfate], resulted very active and selective at low temperatures and its catalytic activity was correlated with the structural characteristics of the metal particles and of the ordered mesoporous support. (C) 2010 Elsevier Inc. All rights reserved.