Microporous aluminosilicates have been synthesized in the presence of organic surfactants according to a procedure based on a two-step sol–gel process at room temperature; varying the surfactant chain length and/or the Si/Al ratio, materials with pore diameters adjustable in the range 1.0–2.5 nm have been obtained; the Al atoms in the as-synthesized samples present tetrahedral coordination, even for materials with high Al content (Si/Al = 6).