Low silica X (LSX) zeolite was synthesised by traditional and microwave heating. In both syntheses the X zeolite showed high crystallinity and purity, low silicon/aluminium molar ratio and a potassium content per unit cell of around 7 wt.%. Microwave heating decreased the time of synthesis respect to the traditional heating under the same conditions. The reduction of the synthesis time was due to uniformity of the heating stage by microwaves. Microwave heating decreased the nucleation and crystallisation time. Basic catalytic properties were checked in the toluene alkylation with methanol. There were no differences in the catalytic activity for toluene alkylation between both LSX zeolites. (C) 2003 Elsevier Ltd. All rights reserved.