The present invention provides an improved process for the preparation of ZSM-5 catalyst of the formula 3.25 Na>2<O. Al>23<.30SiO>2<.zH>2<O where z = 15-20 water molecules per unit cell by autoclaving a mixture of a pre-prepared seeding gel comprising a mixture of a alkali metal cation, an alkali hydroxide, and a silica source in water, and further amounts of silica source and an aluminium source in the presence of an organic solvent with water as a co-solvent.
