Abstract: The present invention relates to a process for producing a crystalline synthetic faujasite of the zeolite Y type wherein a relatively small amount of a zeolite Y seed is thoroughly mixed with sodium silicate at ambient temperature to form an activated sodium silicate system and to such activated system, sodium aluminate is added at ambient temperature. The mixture is then heated and reacted with stirring until the desired cyrstalline product is formed. Zeolite Y is filtered out and then dried.