ZnO/porous silica nanocomposites were successfully fabricated by three different types of synthesis techniques. In all cases, the molecular sieve SBA-16 was used as a porous matrix. The in situ growth the nanoparticles of zinc oxide within the matrix pores was done using either gaseous or liquid precursors. The ex-situ method implied growing of nanoparticles in a colloidal solution with further penetration of the ripened ZnO nanoparticles into the pores of the matrix. Physico-chemical studies of the synthesized ZnO/porous silica nanocomposites showed that the introduction of zinc oxide by any of the methods did not lead to destruction of the structure of the molecular matrix SBA-16. The structure of ZnO nanoparticles, on the contrary, was strongly dependent on the growing method. The best defectless ZnO nanoparticles were obtained by in situ growing using gaseous precursors.