Graphene oxide-reinforced acrylonitrile–butadiene rubber nanocomposites were prepared via solution mixing. The morphology of the graphene oxide was studied, and its successful dispersion within the rubber matrix was confirmed by transmission electron microscopy, scanning electron microscopy, and X-ray diffraction studies. The strong rubber-to-filler interaction was confirmed by swelling and mechanical reinforcing behaviors and thermal stability. Dielectric spectroscopy test indicated a marked improvement of about five times in the real part of permittivity. The electrical conductivity level was close to that of nonconductive materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40640.