The degradation of polyaniline at anodic potentials was studied with in situ UV-Vis spectroscopy of polymer-coated ITO glass electrodes. Spectral changes at high potential values were observed and discussed. Degradation follows first-order kinetics, with rate constants ranging from 8.40 x 10(-6) to 2.93 x 10(-3) s(-1) at electrode potentials of E-NHE = +0.85 to +1.20 V.