The first and remarkably facile synthesis of optically active polyaniline has been achieved via the enantioselective electropolymerization of aniline on indium-tin-oxide-coated glass electrodes in aqueous solution containing (1S)-(+)- or (1R)-(-)-10-camphorsulfonic acid (HCSA). The dark green films of conducting polyemeraldine salt formed under electrostatic conditions (+ 1.1 V versus Ag/AgCl) exhibited strong circular dichroism (c.d.) spectra typical of polymers possessing helical chirality. The quantitative reversal of the c.d. spectrum of the salt grown in (+)-HCSA as opposed to (-)-HCSA suggests that electropolymerization is highly enantioselective, with one helical screw of the polymer chain being preferentially produced depending on the hand of the CSA- anion incorporated. The ready electrosynthesis of optically active polyanilines should facilitate studies of their use in asymmetric synthesis and in chiral chromatography.