The surface modification of sulfur-prevulcanized natural rubber (SPNR) sheets by the polyethyleneimine-functionalized-poly(methyl methacrylate) (PMMA/PEI) nanoparticles was successfully performed via a simple dipping method. The percentage of surface coverage (Cs) of the nanoparticles on SPNR sheets was found to be affected by a variation of nanoparticle latex concentrations and immersion times. The adsorption isotherm of PMMA/PEI nanoparticles on SPNR sheets was analyzed and found to fit well to the Freundlich model. After coating, it can be observed that the presence of PMMA/PEI nanoparticles on SPNR surface had no effects over the SPNR mechanical properties e.g., tensile strength, elongation at break, and hardness. On the other hand, the coated SPNR sheets showed a reduction of surface friction coefficients and interfacial adhesion up to 45 and 59%, respectively. Furthermore, PMMA/PEI nanoparticles adsorbed on the SPNR surface was subjected to stretching and wearing conditions, and found to be stable for at least seven stretching and wearing cycles. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 124: 49-57, 2012