This work presents a resonance tracking atomic force acoustic microscopy (RT-AFAM) quantitative modulus mapping of carbon nanotubes-reinforced acrylonitrile–butadiene–styrene polymer. RT-AFAM average local modulus values registered were in good agreement with those measured by nanoindentation test. RT-AFAM mapping modulus, nanoindentation, and transmission electron microscopy imaging showed that carbon nanotubes reinforcement of acrylonitrile–butadiene–styrene polymer matrix gives an elastic modulus enhancement of approximately 18.3% compared with the polymer matrix alone and showed that this technique provides high spatial resolution and helps to characterize the elastic properties of reinforced thermoplastic polymers and new compound materials at nanoscale. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40628.