Unpromoted and nickel-promoted catalysts were synthesized on the basis of the Anderson heteropoly compounds (NH4)(6 - x) [X-x (OH)(6)Mo6O18] center dot nH(2)O, where heteroatom X is Cr(III), Mn(II), Fe(II), Ni(II), Co(II), Cu(II), Zn(II), or Ga(III), and their activity in the thiophene hydrogenolysis reaction and hydrofining of diesel fraction was examined. It was shown that the most active hydrotreating catalysts under the test conditions in a flow unit were the samples with X = Ni, Mn, or Zn. The catalysts synthesized from the Keggin heteropoly compounds H-4[SiMo12O40] center dot 17H(2)O, H-3[PMo12O40] center dot 19H(2)O, H-3[PVMo11O40] center dot nH(2)O, and (NH4) (x) [V(MoO3)(12)] center dot nH(2)O were tested in the hydrofining of light coker gas oil. The maximum activity was displayed by the catalysts prepared on the basis of the vanadium-containing heteropoly compounds H-3[PVMo11O40] center dot nH(2)O and (NH4) (x) [V(MoO3)(12)] center dot nH(2)O.