Pyrolysis oils are considered as reasonable and promising second-generation biofuels. However, the high oxygen content (26-47 wt.%) in bio-oils leads to a lower energy density than traditional fuels and the strong acidity (pH∼2-3) makes them enormously unstable. Herein, we evaluated hydrodeoxygenation (HDO) of guaiacol (GUA) as a bio-oil model compound over non-sulfide NiMo/Al 2O 3 under conditions close to those of conventional hydrotreatment process (300°C and 7.1 MPa), and the results were compared to those obtained with non-sulfided commercial catalyst CoMo/Al 2O 3. NiMo/Al 2O 3 was found to be superior to the commercial catalyst CoMo/Al 2O 3 with respect to conversion of GUA and HDO level in the liquid product mixture (O/C and H/C molar ratios). The main products for HDO of guaiacol were cyclohexane, methane, cyclohexanol, methyl-cyclohexane, and methyl-cyclopentane. The updated liquid products with C/H and C/O molar ratios close to those of gasoline and diesel were produced. Thus, non-sulfided NiMo/Al 2O 3 are promising catalysts for the treatment of bio-oils.