Optimization studies are carried out for the synthesis of zeolite A by a hydrothermal method using calcined diatomite. Fractional factorial design of experiments along with path of steepest ascent is used to optimize the composition and process parameters. A surface methodology technique is used to obtain the optimum value of the process parameters to maximize the percentage crystallinity of zeolite. It is found that SiO2/Al2O3 molar ratio of 1.31, Na2O/SiO2 molar ratio of 3.61, and temperature of hydrogel formation of 35.7 degrees C give maximum crystallinity of 92 % at the crystallization temperature of 110 degrees C and reaction time of 51 h.