Mesoporous silicas, SBA-15 and HMS, were functionalized with mercaptopropyl groups by the single step procedure. The organomodified silicas and the bare mesoporous silicas were used as supports for CoMo catalysts. The final materials were analysed by several techniques such as N-2 physisorption (BET), DRS UV-vis, XRD, SAXS, TPR and XPS. The catalytic activities were evaluated in the hydrodesulfurization reaction of thiophene. The effect of the two different silica textures on the catalyst activity was rather small. However a significant enhancement of the catalytic activity was observed for the catalysts supported on the functionalized silicas. Taking into account the structural and spectroscopic results, the superiority of the thiol containing catalysts is attributed to the improved dispersion and reducibility of the precursor oxide species. (C) 2010 Elsevier B.V. All rights reserved.