MoS2/Al2O3 and NiMoS2/Al2O3 catalysts were prepared by incipient wetness impregnation of alumina using aqueous solutions of 12-molybdophosphoric heteropolyacid and nickel citrate. Unsupported catalysts were prepared by etching a support made from MoS2/Al2O3 using hydrofluoric acid (Et-MoS2) and thermal decomposition of aluminum tetrathiomolybdate (Ref-MoS2). The activity of the catalysts in hydrodeoxygenation decreases in the series NiMoS2/Al2O3 = Et-MoS2 > MoS2/Al2O3 > Ref-NiS2. On the other hand, the selectivity relative hydrogenation of oleic acid has a different order: Et-MoS2 > MoS2/Al2O3 > Ref-MoS2 > NiMoS2/Al2O3. The unsupported Et-MoS2 catalyst has similar activity to NiMoS2/Al2O3 in hydrodeoxygenation and the highest selectivity, which indicates virtually completion of the hydrodeoxygenation reaction through a hydrogenation pathway without the formation of CO or CO2. These gases display strong inhibiting properties and have a detrimental eject on the environment.