Ni on Al-pillared montmorillonite systems were prepared and tested as hydrogenation catalysts using hydrogenation of benzene as a test reaction. Catalytic activity was evaluated over a temperature range of 70-180 degreesC under atmospheric pressure, in a differential bench scale reactor. The influence of the support on the catalyst activity was studied by varying the Ni loading and modifying the support prior to Ni impregnation. The most active catalyst resulted from Al3+ ion-exchange of the pillared montmorillonite and subsequent introduction of a Ni amount, ca. 12% (w/w), sufficient to form metal aggregates with less pronounced carrier effect.