Mordenite (MOR structure), ZSM-5 and silicalite-1(MFI structure) zeolites have been synthetized by hydrothermal method using 1,6-diaminohexane (DAH) as a structure directing agent. From the characterization of the synthesized materials, it could be deduced that the organic compound acts as a pore-filling in the crystallization of ZSM-5 and Silicalite-1, however the amount of 1,6-diaminohexane incorporated in the mordenite zeolite is low. The effect of alkaline cation shows that sodium and potasium are essential factors governing the crystallization of MOR and MFI zeolites. Pure silicalite-1 zeolite can be obtained in the presence of sodium as well as in the presence of potasium, whereas, mordenite and pure ZSM-5 zeolites can not be synthesized in the absence of sodium.