Stearic acid is a long-chain saturated fatty acid that can be converted into diesel-range alkanes as alternative fuels. In this work, the effects that metal oxide supports with different acid-base properties (Ru/γ-Al2O3 or Ru/MgO) on the product distribution during hydrodeoxygenation of stearic acid was evaluated. The hydrodeoxygenation of stearic acid was carried out in an autoclave batch reactor by varying temperature and pressure using water as a solvent. It was found that ruthenium on acid material was the most active catalysts yielding 4 times higher of alkanes than that of basic material after the reaction. At our best reaction conditions (300 °C, 40 bar H2, 1 h reaction time, catalyst to feed ratio = 1:30), the alkanes obtained from stearic acid for Ru/γ-Al2O3 and Ru/MgO were 34.3 and 8%, respectively.