n-Hexane was isomerized in a micro-catalytic pulse reactor over a series of platinum loaded dealuminated H-MOR and H-BEA catalysts with various Si/Al ratios. Steaming and HCl processes were applied in the dealumination of the two zeolites. TPD data showed that H-MOR zeolite and its dealuminated samples possess higher acid sites number and strength than the corresponding H-BEA zeolite versions, whereas the dispersion of 0.35wt%Pt was higher on the latter samples. The results showed that the steam treatment inhibits the hydroisomerization activity on both zeolites due to the formation of extra-framework aluminum species in the pores of the zeolites as shown from SEM studies. However, acid leaching promotes the catalytic activity by widing the pore opening. Generally, H-BEA containing catalysts either untreated or dealuminated showed higher hydroisomerization activities than the other H-MOR containing catalysts.