A functionalization process with HNO3 acid on carbon nanofibers has been carried out in order to improve the wear resistance of a carbon nanofiber ( CNF)/epoxi resin nanocomposite materials. Friction and wear tests were carried out using ball-on-disk equipment. Results show that the wear volume loss is reduced with CNF content. Therefore, the use of functionalized CNFs in the manufacturing of epoxy matrix nanocomposites achieves to improve both the contact reinforcement/matrix and the filler distribution in the nanocomposite. The wear resistance increases 30% to 40% over the untreated CNF. (C) 2013 Elsevier B.V. All rights reserved.