A process for the transalkylation of alkylaromatic hydrocarbons is disclosed. Transalkylation of alkylaromatic hydrocarbons, such as toluene, is effected at transalkylation conditions in contact with a catalytic composite characterized by a method of preparation whereby a zeolite of the mordenite crystal structure with a sodium content of less than about 5 wt. % as Na.sub.2 O is subjected to an aqueous ammoniacal treatment at a pH of at least about 9.5 and calcined in intimate admixture with a refractory inorganic oxide to form a catalytic composite therewith.