Mixed ionic-electronic conductors in the family of La x Sr1–x Co y Fe1–y O3–δ have been widely studied as cathode materials for solid oxide fuel cells (SOFCs). However, the long-term stability was a concern. Here we report our findings on the effect of a thin film coating of La0. 85Sr0. 15MnO3–δ (LSM) on the performance of a porous La0. 6Sr0.4Co0.2Fe0.8O3–δ (LSCF) cathode. When the thicknesses of the LSM coatings are appropriate, an LSM-coated LSCF electrode showed better stability and lower polarization (or higher activity) than the blank LSCF cathode without LSM infiltration. An anode-supported cell with an LSM-infiltrated LSCF cathode demonstrated at 825 °C a peak power density of ∼1.07 W/cm2, about 24% higher than that of the same cell without LSM infiltration (∼0.86 W/cm2). Further, the LSM coating enhanced the stability of the electrode; there was little degradation in performance for the cell with an LSM-infiltrated LSCF cathode during 100 h operation.