Isobutane is an important raw material in the production of synthetic rubber and oxygenates for octane-boosting compounds. Highly acidic zeolites, such as mordenite, have been proposed as environmentally-friendly catalysts. Dealuminated and non-dealuminated mordenite zeolite catalysts (SiO 2/Al2O3 12.8) modified with 0.5, 1 and 2 wt-% of Pt were tested for the isomerization of n-butane. 0.5 wt-% Pt-MOR exhibited the highest isomerization efficiency (IE), e.g. defined as iC4/ (C3+C5) and the lowest deactivation at the conditions tested. Upon dealumination, the activity of the 0.5 wt-% Pt-modified mordenite zeolites decreased but the selectivity to isobutane was the highest. This is the combined effect of extra-framework Al and a less acidic catalyst. Calcination of dealuminated Pt-modified mordenite resulted in enhanced formation of micropores and there by increase in the initial conversion of n-butane.