The liquid-phase hydrodebromination of bromobenzene with molecular hydrogen over palladium supported catalysts was studied. The reaction was found to be structure-sensitive as regards both the initial activity and the final conversion (deactivation). The influence of the palladium content and the catalytic support effect on the initial activity were negligible in catalysts of similar metal dispersion. The supports tested, viz. SiO2/AlPO4, ZrO2 and MgO, significantly affected the catalyst deactivation. On the other hand, the addition of NaOH to the reaction medium had no effect on the initial activity, but clearly helped the reaction to be completed and avoided passivation of the catalyst. In summary, the activity of the catalyst depends almost solely on its metal particle size, whereas the deactivation of the active phase is decisively influenced in addition to metal particle size, by the nature of the catalyst support and the presence of a base in the reaction medium.