The sinthesis conditions of a series of monodisperse crystals of ZSM-5 zeolite, silicalite-1, and Fe-silicalite-1 with an average particle size in the range of 30 to 450 nm have been determined. The kinetic features of the silicalite-1 crystallization at low temperatures (60-90 degrees C) and atmospheric pressure have been studied. The effective activation energies of silicalite-1 nucliation and crystal growth have been determined to be 95 +/- 7 and 100 +/- 7 kJ/mol, respectively. The influence of the synthesis time and temperature as well as the silicon source concentration on the size of the MFI type nanocrystals has been studied.