Catalytic performance of beta zeolites derived from bagasse fly ash for methanol dehydration to dimethyl ether, alternative fuel, was investigated. Amorphous silica extracted from bagasse fly ash, a tetraethylammonium hydroxide (TEAOH) were used as a precursor and a template for synthesis of beta-zeolites, respectively. Beta zeolites could be synthesized at a constant hydrothermal temperature of 135 degrees C and a constant initial pressure of 3 bars under the nitrogen atmosphere. The crystallization time and Si/Al ratio were 48 h and 15, respectively. These conditions gave the highest crystallinity for beta zeolites with a crystal size of 0.51 m as well as a Brunauer-Emmett-Teller surface area of 844 m(2) g(-1). Beta zeolites with the Si/Al ratios of 15.8 and 24.6 were used as catalysts for methanol conversion to dimethyl ether. Beta zeolites with the Si/Al ratios of 15.8 and 24.6 have the % yields of 84 and 60, respectively. According to the result of NH3-TPD, the beta zeolites with the Si/Al ratio of 15.8 showed higher acidity than beta zeolites with a Si/Al ratio of 24.6. Therefore, the beta zeolites with a Si/Al ratio of 15.8 were more efficiency in methanol conversion reaction than beta zeolites with a Si/Al ratio of 24.6.