Montmorillonite pillared with polyoxications of Al and GaAl has been modified with Ce and the effect of the presence of the Ce3+ ion on the activity of catalysts obtained from the PILC products by impregnation with Pt has been investigated. Through acidity studies and catalytic tests the presence of Ce has been found to produce a substantial increase in the conversion of n-heptane and in selectivity towards the cracking products, independently of the greater stability generated in products with mixed Al-Ga pillars. This also corresponds to the increase in both the number and strength of acid centers produced by the addition of Ce.