Gas liquors, tar oils, and tar products resulting from the coal gasification of a high-temperature Fischer-Tropsch plant can be successfully refined to fuel blending components by the use of severe hydroprocessing conditions. High operating temperatures and pressures combined with low space velocities ensure the deep hydrogenation of refractory oxygen, sulfur, and nitrogen compounds. Hydrodeoxygenation, particularly the removal of phenolic components, hydrodesulfurization, and hydrodenitrogenation were obtained at greater than 99% levels using the NiMo and NiW on gamma-Al2O3 catalysts. Maximum deoxygenation activity was achieved using the NiMo/gamma-Al2O3 catalyst having a maximum pore size distribution in the range of 110-220 angstrom. The NiMo/gamma-Al2O3 catalyst, which also has a relatively high proportion of smaller pore sizes (35-60 angstrom), displays lower hydrogenation activity.