A series of five samples (6.80, 15.80, 20.10, 21.45, 22.00 Co2+ ions per unit cell) of Co2+ exchanged X-zeolites were prepared by cation exchanged method. The decrese in percentage exchange with increase in Co2+ ions in exchange solution suggest replacement of NaX ions from the supercages and also “volume effect” the zeolitic water contents and thermal stability of hydrated zeolite samples unexchanged and exchange were investigated by using thermo gravimetric analysis (TGA) and differential thermal analysis (DTA) techniques, under a constant flow of nitrogen as purge gas. The TGA study indicated total weight loss percentage of the zeolite samples from 18.87% to 26.70. the zeolite water contents and thermal stability increased with increase Co2+ ions in the zeolitic X. Two exothermic DTA curves at 585oC and 887oC for NaX and one up to about 830oC were recorded for Co X-zeolite samples, which indicated the collapse of crystalline aluminusilicate framework.