To simultaneously improve electrical conductivity and toughness of polyamide 6 (PA 6), carbon black (CB) nanoparticles and maleic anhydride grafted polyethylene-octene copolymer (POE-g-MA) were compounded with PA 6 by melt compounding, and the influences of CB and POE-g-MA components on the electrical conductivity and mechanical properties of PA 6 nanocomposites were investigated. The addition of CB improves the electrical conductivity and Young's modulus of PA 6. With 40 wt % POE-g-MA and 15 wt % CB, the nanocomposite exhibits a high notched impact energy of 73.9 kJ/m(2) and an electrical conductivity of 7.1 x 10(-6) S/m. Interestingly, the presence of POE-g-MA reduces the electrical percolation threshold of the PA 6 nanocomposites due to the selective localization of CB in the PA 6 matrix. Compared to PA 6/CB binary nanocomposites, the ternary nanocomposites exhibit both higher electrical conductivity and supertoughness.