Abstract: The adsorption of methanol, isobutene and MTBE on zeolite HBT6 was investigated using IR spectroscopy. The mechanism of synthesis of MTBE from methanol and isobutene over zeolite HBT6 was studied based on adsorptive states of reactants and product over the catalyst and intrinsic kinetic experiments. Methanol, isobutene and MTBE were probably adsorbed on OH groups of the zeolite, and adsorbed isobutene molecules were π-complexes which could, easily, turn into tertiary butyl C +. Reaction of methanol with isobutene over the zeolites takes place according to the L-H mechanism and the rate-determining step is the reaction of adsorbed methanol with adsorbed isobutene. TPD following adsorption showed that some of the methanol molecules were strongly adsorbed on the catalyst. It might be a disadvantageous factor.