Nanostructured coatings on metals, plastics, and textiles have numerous applications, for example, as antifogging and self-cleaning coatings as well as protective coatings against corrosion. heat, or wear. Here the preparation at low temperature of dense nanostructured tetragonal ZrO2 coatings via a modified emulsion precipitation method is presented. The method, which involves the controlled preparation, crystallization. and densification of non-agglomerated ZrO2 nanoparticles, opens up the possibility of applying nanocoatings of high-melting oxides to steel or plastic, where low temperatures are required.