The effect of ion exchange of mordenite on the catalytic behavior of the alkane hydroisomerization reaction over platinum loaded H-form modenite catalysts (Pt / HM) was investigated. The degree of sodium removal and changes in the SiO2/Al2O3 ratio were examined separately. The correlation between acidic properties and activities is presented. It has been proved in this study that chlorofluorocarbon treatment of Pt/HM samples was effective for enhancing the catalytic activity of alkane isomerization reactions. Optimum treatment conditions are given to obtain higher level of isoparaffin yields.