The reduction of oxygen on nickel-doped lanthanum strontium ferrite was studied by current interrupt cyclic voltammetry. Nickel doped on the B site of the perovskite ranged from 0 to 40%. Nickel strongly influenced the sintering of the films. The minimum temperature at which a stable adherent robust film could be formed increased with nickel content. The electrochemical performance for reduction of oxygen was compared with nickel content. Undoped lanthanum strontium ferrite consistently showed greater activity than the doped materials. The data were further analyzed to obtain the exchange current density as a function of temperature and then further analyzed to obtain the activation energy and pre-exponential factor. These values did not correlate with nickel composition but did correlate with one another. The variation in performance was tentatively attributed to subtle variations in microstructure. (C) 2003 The Electrochemical Society.