Cobalt promoted Mo/b (Beta zeolite) catalysts were prepared with different metallic loadings (0.5–1.5)by a co-impregnation method. The catalytic activities of the synthesized catalysts were investigated forthe selective hydrocracking of tetralin and pyrolysis fuel oil (PFO) into mono-aromatic hydrocarbons(MAH) such as benzene, toluene and xylene (BTX) in afixed-bed reactor system. Prior to using theCoMo/b catalyst for crude PFO hydrocracking, different reaction parameters (including metallic loading,temperature, H2 pressure, and LHSV) were investigated for the hydrocracking of a model feed, tetralin, todetermine the best conditions for maximum BTX yield. The CoMo(0.5)/b catalyst with a Co/Mo ratio of0.5 produced the highest MAH yield of 62.6% at 99.5% conversion of tetralin, continuously for 140 h ofreaction time without any deactivation. Furthermore, the CoMo(0.5)/b catalyst was found to be superioramong the tested CoMo/b catalysts for hydrocracking real feed PFO, and it produced a maximum MAHyield of 54.8% at 99.1% conversion of PFO. The synthesized catalysts were characterized using differentcharacterization techniques, including BET, NH3-TPD, SEM-EDS and ICP, to evaluate their physiochemicalproperties and determine the active sites present in the catalysts.