The conversion of MeOH over HT zeolite was investigated in a fixed-bed reactor, with the zeolite being prepd. from NaT by ion exchange with aq. HCl (appreciable dealumination) or NH4Cl. High yields of C2H4 were obtained with NH4Cl-exchanged zeolites with 45% decationization, and high propylene yields with low HCl or NH4Cl exchanged catalysts. Low MeOH partial pressures and short residence times favored the formation of lower olefins. The lowest coking rates were obsd. at 693K. The catalytic activity decreased slowly with increasing no. of reaction/regeneration cycles. The C>2 products followed the Schulz-Flory distribution.