The effect of the presence of palm fatty acid distillate (PFAD) during co-processing with light gas oil (LGO) in hydrodesulfurization unit has been carried out in a near adiabatic, pilot-scale, and fixed-bed hydrotreating reactor, over commercial CoMo/Al2O3 under 280-350 degrees C, 25 barg, H2/feed ratio of 630 Nm(3)/m(3) and 0.75 h (1). The amount of PFAD 5, 8, 12, and 25 wt% of PFAD in LGO was the feed mixtures. High conversion range on both desulfurization and deoxygenation reactions were achieved by every fraction of PFAD. The hydrocarbon products contained sulfur lower than 50 ppmw and neutralization number lower than 0.1 mg KOH/g. These products can be claimed as EURO 4 diesel following EN 590. The presence of PFAD in LGO improved the cetane index of the liquid products while lowered the product density. Highly heat effect was observed by an increasing of the reactor temperature up to 62 degrees C at the reactor outlet in the case of 25 wt% of PFAD. The increasing of the reactor temperature was resulting from an increasing amount of PFAD in LGO. The higher amount of PFAD slightly facilitated deoxygenation reaction, but impeded hydrodesulfurization reaction. The temperature rise also increased hydrocracking reaction evidenced by the lower contribution of total n-paraffin to the product mixture at higher PFAD in LGO. Finally, the hydrogen consumption was observed as linearly increased with an increasing amount of PFAD. The consumption was then theoretically calculated and extrapolated for hydrotreating of pure PFAD at 300 and 344 Nm(3)/m(3), respectively. An additional hydrogen consumption of 44 Nm(3)/m(3) was studied and discussed. (C) 2017 Elsevier Ltd. All rights reserved.