This contribution describes the effect of SBA-15 support modification with variable quantity of TiO2 (0, 10, 20, 40 and 60 wt%) on the catalytic response of supported gold catalysts in CO oxidation. All gold catalysts were prepared by the deposition-precipitation method. These catalysts were characterized by chemical analysis (ICP), N-2 adsorption-desorption isotherms, X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), high resolution transmission electronic microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). Catalytic activity was found to increase with the TiO2 loading even though this increase was not lineal: the highest catalytic activity was observed for the catalyst loaded with 10 wt% TiO2. This behavior is explained in terms of the quantity of Au+ species present on the surface of gold particles. In addition, an Au/TiO2 reference sample was prepared and tested in CO oxidation reaction. This Au/TiO2 catalyst exhibited the highest activity due to the higher gold dispersion achieved on the TiO2 substrate. The importance of both Au+ and Au-0 species present on the catalysts surface on the performance in the target reaction is discussed. (C) 2009 Elsevier B.V. All rights reserved.