Single-wall carbon nanotubes-filled polystyrene (SWNTs-PS) composites with 0-1.0% content have prepared successfully by a modified version of the suspension polymerization technique showed distinctive physical features, such as uniform black coloration and high solubility in toluene and tetrahydrofuran (THF). An adsorbed polymer layer on the nanotube bundles was found to contribute to a better dispersion of the inorganic nanoreinforcement. Stable suspension solution was formed by dispersing a hydrophobic monomer into water under high ultrasonic and adequate shear force conditions. DC resistivity and AC impedance measurements performed on the SVTNTs-PS composites showed that the presence of SWNTs significantly modifies the electrical impedance of the composites. The obtained composites range from pure semiconductor to clear ohmic behavior as SWNTs loading increases in the composites. (c) 2005 Published by Elsevier B.V.