Magic angle spinning considerably narrows the 1H NMR lines in zeolite H-ZSM-5. With this technique 2 NMR lines are obsd. due to protons in either H2O mols. around silanol groups and Broensted acidic sites or structural OH groups at these sites. The desorption and adsorption behavior of H2O at these sites were studied for samples with different Si/Al ratios and ion-exchange treatments.