The present invention relates to a process for producing a plurality of hollow inorganic nanoparticles, which process comprises: (a) contacting a first monomer and a second monomer in a solvent to produce a composition comprising the solvent and a plurality of polymer nanoparticles; (b) adding an inorganic compound precursor to the composition comprising the solvent and the plurality of polymer nanoparticles to produce a composition comprising the solvent and a plurality of inorganic compound- coated polymer nanoparticles; (c) adding an additional amount of the first and second monomers to the composition comprising the solvent and the plurality of inorganic compound-coated polymer nanoparticles to produce a composition comprising the solvent and a plurality of composite nanoparticles; and (d) heating the plurality of composite nanoparticles to produce the plurality of hollow inorganic nanoparticles, wherein in step (a) the first monomer and the second monomer are contacted in the solvent at a temperature of at least 30°C. The present invention also relates to plurality of hollow inorganic nanoparticles and uses thereof.