Co-PMo catalysts were prepared from the 12-molybdophosphoric heteropolyacid and cobalt citrate on the base of freshly-synthesized alumina and mixed MCM-41-Al2O3 material. Carriers and catalysts were characterized by the following techniques: X-ray powder diffraction, low-temperature N2 adsorption, NH3-TPD, Raman spectroscopy, X-ray photoelectron spectroscopy and high-resolution transmission electron microscopy. Prepared catalysts were tested in hydrodesulfurization of dibenzothiophene and hydrogenation of naphthalene. It has been shown that mesoporous silica incorporation into alumina can improve morphological properties of the CoMoS active phase as well as the overall HDT activity.