This study was aimed at evaluating the effects of reaction pressure and temperature on toluene disproportionation using a ZSM-5-based catalyst impregnated with molybdenum. The results of the study showed that both toluene conversion and xylene selectivity were strongly dependent on temperature, pressure, and the kind of carrier gas used. Toluene conversion compared at the same temperature and pressure was found to be higher when nitrogen instead of hydrogen was used as the carrier gas. For both carrier gases, it was found that toluene conversion increased,with both pressure and temperature. Furthermore, it was observed that catalyst deactivation was more rapid and more severe with nitrogen as the carrier gas than with hydrogen.