The t-butanol dehydration over basic ETS-10, ETAS-10 and AM-6 has been investigated. All these as-synthesised materials catalyse this reaction in a very similar fashion yielding remarkably high selectivities for isobutene, which are independent of both reaction conditions and conversion levels. The catalyst decay was more profound at lower reaction temperatures (ca 200 degrees C), whereas no decay was observed at higher temperatures (ca 300 degrees C). The basic sites of these materials are purported to be responsible for the excellent catalytic performance.