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Two NiMo catalysts were prepared by different methods using citric acid to assess the effects of preparation method on dibenzothiophene hydrodesulfurization (HDS) and simultaneous HDS and hydrodenitrogenation: co-impregnation and post-treatment. Characterization of oxide catalysts was performed by nitrogen physisorption, X-ray diffraction, and temperature-programmed sulfidation, while sulfided samples were characterized by temperature-programmed reduction (TPR-S) and NO chemisorption. The catalytic evaluation for HDS reaction was performed in a three-phase reactor, with and without quinoline. The direct desulfurization is the preferred route for the HDS of dibenzothiophene. The post-treatment method was more efficient in achieving higher catalytic activity than co-impregnation. Furthermore, TPR-S and NO chemisorption results show an enhancement in the density of active sites on the catalyst prepared by post-treatment, being more hydrogenating than the one synthesized by co-impregnation. Although the catalyst prepared by post-treatment was more inhibited by quinoline, it remained more active than the one synthesized by co-impregnation.