We have found that the current range is divided into two parts for the appearance of potential oscillation during methanol oxidation on polycrystalline platinum at 315 K when the methanol concentration is between 10 and 0.03 mol dm −3 (M). The current range for oscillation disappearance, named ΔI (od), increases with a decrease in the methanol concentration. At currents below the ΔI (od), the oscillation waveform is always a large-amplitude and long-period (sometimes of the order of an hour) oscillation, named oscillation L. At currents immediately above the ΔI (od), a small-amplitude and short-period oscillation, named oscillation S, is observed for 0.03 to 0.1 M methanol and oscillation L is for 0.3 to 10 M methanol. For the latter methanol concentrations, oscillation S also becomes observed at higher currents. Such a ΔI (od) has not been found for potential oscillations during formic acid or formaldehyde oxidation and, thus, the existence of the ΔI (od) is distinctive to potential oscillations during methanol oxidation.