Resistometry, UV-Vis and Raman Spectroscopy have been employed as in-situ methods for the determination of the overoxidation potential of polypyrrole (PPy). These methods all show that the onset of overoxidation begins at potentials as low as 0.65V v Ag/AgCl for unsubstituted PPy. They also show a strong dependence of overoxidation potential on the pH of the supporting electrolyte, with an increase in stability at lower pH's.