The FER-type zeolite was found to be a reliable catalyst for DME synthesis via both direct CO2 hydrogenation or gas phase methanol dehydration. In this work, the effect of the crystal size of FER-type zeolites on the catalytic behavior during methanol-to-DME conversion is studied. A series of FER-type crystals ranging from 0.1 mu m to 10 mu m in size were synthesized and their physicochemical properties (e.g. crystal morphology, acidity, textural characteristics) analyzed. The catalytic performance of FER-type catalysts was studied in a wide range of reaction temperatures (120-280 degrees C). The set experimental data show that the catalytic effectiveness of FER-type catalysts in terms of methanol conversion, DME selectivity and coke resistance, can strongly be improved by reducing the zeolite crystal size.