It is possible to fabricate nanostructures of 25.5 nm by replication using injection molding. In this study, a silicon calibration grating was used as a mold insert to replicate high-quality nanostructures with a simple custom-made injection machine. The replicated grating with 25.5-nm nanofeatures made with a polymer was of high quality when a high mold temperature was employed and the mold was evacuated. (C) 2007 Wiley Periodicals, Inc.