Montmorillonite clay from Brazil was pillared with aluminium polyhydroxications. The influence of aging of the pillaring solution and the concentration of the clay suspension on the properties of the prepared materials was studied. The materials were characterized by chemical analysis, XRD and pore analysis by N-2 adsorption. The catalytic properties were evaluated in the cumene cracking reaction. Results showed that the pillarization process increases the basal spaces of natural clay from 9.7 to 18.5 angstrom and the surface area from 41 to 300 m(2)/g.285777782