Fine molybdenum-carbide catalytic systems were obtained by the method of mechanical activation in an inert atmosphere. The composition and morphology were investigated, the catalytic behavior of molybdenum-carbide systems was estimated in the hydrotreatment process of vacuum residue.    In the presence of a molybdenum-carbide catalyst, a decrease in the coke yield by more than three times is observed compared to the coke content obtained with the same temperature-time parameters of the process without a catalyst.