The impedance characteristics of poly-o-aminophenol film electrodes in NaClO4 0.4M + HClO4 0.1M electrolyte have been measured in the frequency range 0.01 < f < 10(3) Hz and at two different thicknesses. The experimental results can be interpreted through a simple charge transfer resistance in parallel with a constant, capacity at high frequencies and the redox capacity in series with the Nm resistance at low frequencies. The analysis of the impedance response allows to the electrochemical rate constant, the concentration of redox centers in the film, the film conductivity and the diffusion coefficient of the elections to be determined.