Co-coking is the thermal treatment of a petroleum stream and coal; this technique has been explored in order to include coal-derived components and bring more thermal stability to petroleum distillates. Previous research has identified co-coking as one way to include the desired coal-derived compounds into the jet fuel fraction. An original decant oil was hydrotreated under different severity levels, giving origin to three hydrotreated versions; each decant oil was blended with coal. The conditions are isothermal, varying reaction time and pressure. The main objective is to establish the best conditions to obtain higher amount of coal-derived compounds through the oil assessment. Dr. David Clifford set the method for the GC-MS to characterize oils having a wide-range molecular weight and boiling point distribution; his method was applied to the current work. His training and discussions were decisive to assess the oils using other techniques such as simulated distillation and 1H NMR.