The hydroisomerization of a C-10-C-13 n-alkane mixture was investigated over six bifunctional platinum-containing zeolite catalysts with 10-and 12-membered ring pore systems. The catalysts with 12-membered-ring zeolites are more active than those with 10-membered-ring zeolites. In Contrast, higher yields of the desired mono-branched isomers are obtained on the 10-membered-ring zeolites due to shape-selectivity effects. For the 10-membered-ring zeolites, higher reaction temperatures are required for achieving the maximum isomer yields, which leads to more cracking products compared to the 12-membered-ring zeolites.