This work presents a comparative study of supporting electrolyte effect on the protection ability of poly(carbazole) films deposited on 304 stainless steel. Tetrabutylammonium, sodium and lithium perchlorate salts were used as supporting electrolyte in the investigation. Poly(carbazole) films were synthesized by electropolymerization of carbazole using cyclic voltammetry from acetonitrile medium containing monomer and supporting electrolyte. Protective properties of poly( carbazole)s were investigated in 1 M H2SO4 solution using E-ocp-t curves, Tafel polarization and electrochemical impedance spectroscopy. Corrosion test results revealed that supporting electrolyte affects conductivity of deposited films. Poly(carbazole) synthesized from tetrabutylammonium perchlorate exhibited better protection performance than the other poly(carbazole)s. (C) 2013 Elsevier Ltd. All rights reserved.