We report on a simple and efficient linewidth modification of imprinted nanopatterns by heat and plasma assisted oxidation. Addition of oxygen was found to be critical in reducing the process temperature and the efficiency of the linewidth reduction. The linewidth defined by nanoimprint lithography (NIL) can be reduced more than 60% without any deterioration of structural details of the fine patterns. Weakened material dependence of this oxidative process was verified from the results obtained from the experiments adopting various materials. Furthermore, it was also demonstrated that this method could be applied in the modification of different types of nanopatterns prepared by the NIL. (C) 2014 Elsevier B.V. All rights reserved.