Polymer nanocomposites can exhibit superior multi-functional properties if they possess phase separatedmorphology at the nanoscale. Despite the huge potential of these materials, there are severalfundamental issues including the ultimate microstructures, which need to be resolved to tailor differentphysical and mechanical properties required for specific applications. A 'ternary nanocomposites' approach is adopted to prepare electrically conductive and super-tough1 (in terms of notched impactenergy) hybrid polymer nanocomposites (polyamide 6/carbon nanotube/elastomer) that possess betterproperties than either of the constituent binary polymer nanocomposites (polyamide 6/carbon nanotubesand polyamide 6/elastomer). The individual roles of the nano-fillers involved in achieving multifunctionalityare emphasized. The level of property enhancements of ternary nanocomposites dependsessentially on the microstructure inducing a volume exclusion effect and the capability of fillers toactivate the plastic deformation mechanisms in the matrix.