The process of methanol conversion to dimethyl ether over an H-SAPO-34 molecular sieve was studied, using the catalyst as synthesized or formulated in an alumina matrix. The experiments were performed on the temperature interval 100-250 degrees C, liquid space velocities of 1-5 h(-1), and pressures between I and 10 bar. The results evidenced a high catalytic activity of the H-SAPO-34 molecular sieve, providing in these conditions a practically total methanol transformation to dimethyl ether. Also, a special run, performed at 180 degrees C, with an Output composition close to chemical equilibrium, showed no significant change of catalyst activity during an on-stream time of 50 h, this proving a good stability and resistance to deactivation. A published rate expression for the methanol dehydration reaction was selected and adapted to describe the experimentally observed process kinetics.