A process is described for the preparation of zeolitic catalysts in the form of microspheres, comprising zeolite and oligomeric silica, characterized by a high mechanical resistance. The process consists in subjecting to rapid drying the suspension, to which tetra-alkylorthosilicate is optionally added, resulting from the synthesis of zeolite by hydrothermal treatment at autogenous pressure of the reagent mixture containing tetra-alkylammoniumhydroxide as templating agent, and subjecting the product resulting from the drying to calcination.