Multiwalled carbon nanotubes (MWNTs) have been widely used as nanofillers for polymer reinforcement due to their excellent mechanical properties. However, for MWNTs-based polymer composites, the rigid surface, poor dispersibility and weak interaction of MWNTs still limited the potential and further application in mechanical reinforcement. In this paper, we report a facile method for functionalization of MWNTs with Kevlar nanofibers. Kevlar nanofiber-functionalized multiwalled carbon nanotubes (KNCNTs) were successful obtained by the simple process of solution mixing followed with sonication. The as-prepared KNCNTs can be well dispersed in water and dimethylsulfoxide (DMSO) solvents. In the next, poly(vinyl alcohol) (PVA) and poly(methyl methacrylate) (PMMA) were chosen as model polymer for investigating the reinforcement effect of KNCNTs. The results of tensile tests demonstrated that the ultimate tensile strengths and Young's modulus of KNCNTs/PVA and KNCNTs/PMMA nanocomposite films were significantly improved. The KNCNTs have an advantage over the pristine MWNTs for polymer reinforcement. (c) 2013 Elsevier B.V. All rights reserved.