Hydroisomerization and hydrocracking of n-heptane on Pt-containing HMCM-22, HBeta and on composites with MCM-41 and SiO2 were investigated at 20 bar pressure in the temperature range from 493 to 593 K. The composites showed higher activity and selectivity in isomerization compared to the simple Pt-containing zeolites. The improvement in the catalytic properties was much higher with MCM-22, which has a smaller pore system than with Beta. The higher activity and especially the higher selectivity were explained by the faster adsorption and desorption in the composites. It seems that the transport properties are the most important parameter controlling the final catalyst selectivity.