Conductive and flexible carbon fiber (CF) reinforced polydimethylsiloxane (PDMS)/polypyrrole (PPy) composites were synthesized electrochemically. Electrochemical synthesis was performed at + 1.1 V using p-toluenesulfonic acid as supporting electrolyte and water as solvent. Composites were characterized by thermal gravimetric analysis, scanning electron microscopy (SEM), conductivity measurements and mechanical tests. Conductivities of composites were observed in the range of 2.2-4 S/cm. SEM studies show that CFs were coated by PDMS/PPy matrix uniformly. In mechanical tests, it has been observed that tensile strength of composites increased with increasing CF content. Higher percent elongation was achieved by the addition of PDMS. Highly flexible, foldable and mechanically strong conductive composites were obtained. (C) 2003 Elsevier Ltd. All rights reserved.