We have tested our pilot-scale delayed coker for reproducibility. The process repeatability of our delayed coker, in terms of gas, liquid, and solid yields, is very good. The work described in this study essentially addresses the liquid products isolated from the process of delayed coking. A blend of Pittsburgh seam bituminous coal (EI-186) and a decant oil (EI-107) were co-coked in the pilot-scale delayed coker. Applied temperatures and feed material amounts were for similar for the experiments chosen in this study. Reproducibility of yields from co-coking of coal with decant oil in four separate experiments was shown to be excellent. Proton and carbon NMR analyses of the overhead liquid products showed that even though there were slight changes in the integration of 1H and 13C NMR spectra, the standard deviation was low for the time-dependent samples. Similated distillation gas chromatography analyses of overhead liquids showed that the separated fractions (cut point ranges for gasoline, jet fuel, diesel, and fuel oil cuts) were reproducible between runs. For the delayed coking experiments, the boiling point ranges and chemical compositions in co-coking experiments were found to be reproducible.