Different oxidation levels, regarded as polaron, bipolaron, and metallic states, are usually found in conjugated heterocyclic polymers. We found that poly(3,4-ethylenedioxythiophene) (PEDOT) also has these different oxidation levels, using in situ UV-VIS-NIR spectroscopy. The transitions between the different oxidation levels were, however, never clearly observed in cyclic voltammetry (CV). Instead it usually shows a broad oxidation peak and two reduction peaks. The CV of PEDOT at macroelectrodes shows a pair of redox peaks separated by 0.9 V at low scan rates, indicating two irreversible electron transfer steps. Using an ultramicroelectrode, we found these two pairs of redox peaks in PEDOT, as well as for poly(3-methylthiophene) (PMeT). These two peaks cannot be explained by the existence of two forms of the materials, whether due to two different conjugation lengths, crystalline or noncrystalline phases, or created by conformational changes. We deduced that there should be a third redox peak. With fast scan cyclic voltammetry both PEDOT and PMeT on ultramicroelectrodes showed three reduction peaks and two oxidation peaks. We find three ill-resolved pairs of peaks in the CV of PEDOT in 1,1,1,3,3,3-hexafluoro-2-propanol (HFA) electrolytes, which was reported to be able to stabilize radical cations. Only at low temperatures can we find three reversible pairs of redox peaks in the ultramicroelectrode studies. We attribute the three peaks to three redox steps on conversion from the neutral state to polarons, from polarons to bipolarons, and finally from bipolaron to the metallic state, each step involving a one-electron transfer.