Current fluctuations at potentiostatically controlled point electrodes of Pt, La0.85Sr0.15MnO3 (LSM), and Ni on yttria-stabilized zirconia (YSZ) surfaces are determined at 1000 degrees C. For the oxygen reduction process on Pt electrodes, characteristic sawtooth-shaped, low-frequency fluctuations are observed. At temperatures below 900 degrees C the fluctuations cease. At LSM oxygen electrodes and Ni hydrogen electrodes the fluctuations are similar in amplitude and frequency, but the characteristic shape is not observed. Also some spectacular, but not easily reproduced, observations on Ni electrodes in hydrogen/water atmosphere are presented for discussion. The origin of the observations is not known at present, but it appears likely that they are related to the activation/deactivation mechanism of solid oxide fuel cells. (c) 2005 The Electrochemical Society.