The present invention relates to highly ordered arrays of nanoholes in metallic films and to an improved method for producing the same. The method according to the invention for producing an highly ordered array of nanoholes in metallic films on a substrate comprises the following steps: a) providing microspheres comprising poly-N-isopropylamide (polyNIPAM), the microspheres being selected from pure poly-N-isopropyl-amide (polyNIPAM) hydrogel microspheres and polymeric or inorganic beads carrying poly-N-isopropylamide (polyNIPAM) hydrogel chains, b) coating an aqueous dispersion of said microspheres onto a substrate and drying the dispersion, which results in a non-close packed ordered array of the microspheres, c) generating a metallic film on the substrate, d) removing the microspheres from the surface of the substrate which results in an ordered array of nanoholes on the substrate, and e) optionally increasing the thickness of the metallic film by selective electroless plating.