Co(Ni)MoS/Al2O3 catalysts have been prepared from ammonium 10-dodecamolybdodicobaltate (NH4)(6)[Co2Mo10O38H4] (further, Co2Mo10HPC) and cobalt(nickel) salts of 10-dodecamolybdodicobaltic acid H-6[Co2Mo10O38H4] (hereinafter, Co(2)Mo(10)HPA). It has been found that a high activity of the Co(Ni)(3)-Co(2)Mo(10)HPA/Al2O3 catalysts in the hydrodesulfurization and hydrogenation reactions is due to the formation of a nanostructured type II CoMoS phase via the contact of the metals (Mo and Co(Ni)) at the molecular level. The use of Ni as a copromoter in the Ni-3-Co(2)Mo(10)HPA/Al2O3 catalyst leads to a simultaneous increase, compared with Co-3-Co(2)Mo(10)HPA/Al2O3, in the linear size of nanoparticles and the number of MoS2 layers in the packing of active phase. The nature of the promoter X has a substantial effect on the properties of X3Co2Mo10HPC/Al2O3 catalysts. It has been found that the catalysts with X = Co exhibit the highest activity in the hydrodesulfurization reactions and those with X = Ni, in hydrogenation reactions.