The high and low frequency capacitances of polyaniline electrode in different acid medium were analyzed as a function of counter ions, redox states and film thickness. The corresponding double layer and redox capacitances were discussed in terms of variables affected in the growth of polyaniline film. The redox capacitance has been found to be predominant over double layer capacitance in the overall capacitance of the polymer film in the given electrolyte composition and a comparative analysis have been made. (C) 2002 Elsevier Science B.V. All rights reserved.