Characterization of polyaniline (PANI) by electrochemical and spectroscopic techniques are presented. The electrochemical investigation reveals the influence of the dopant acid on the kinetic parameters of polyaniline films: exchange current density (I-0) and the cathodic transfer coefficient (alpha(c)). UV-Vis spectra of thin films of polyaniline in N-metil pyrrolidine solutions indicate the increase of the absorbance with the number of deposition cycles, N. The inhibition of polymer degradation in thick films was confirmed by these spectra.