An investigation is made of the electrochemical response of poly(o-methoxyaniline) films obtained by chemical and electrochemical polymerization in aqueous hydrochloric acid media. The influence of different synthesis techniques and electrochemical measurement conditions (eg number of cycles, monomer concentration, pH of electrolyte solution) on the electroactivity of the poly(o-methoxyaniline) films was analysed. The voltammetric response of electropolymerized films showed two well-defined redox processes similar to those observed for parent polyaniline. The growth of an intermediate redox couple and/or the gradual disappearance of the redox process at more positive potentials were attributed to polymer degradation. Evidence is given of degradation by chemical crosslinking and chain scission. The relationship between the polymer structure and its electroactivity is discussed.