(La0.6Sr0.4)0.95FeO3-δ/ Sm0.2Ce0.8O2 (70:30 w/w) and (La0.6Sr0.4)0.995Co0.2Fe 0.8O3-δ/Gd0.1Ce0.9O 2 (50:50 w/w) cathodes screen printed on anode-supported cells were tested for 500 h under different conditions by using a Taguchi matrix that combined cathode processing parameters (cathode material, thickness, sintering temperature) and operation conditions (temperature, current density, air flux, air humidification and chromium presence). Individual effect of each control factor on cell performance degradation was evaluated: chromium poisoning, air humidity and temperature were classified, in such order, as the most influencing parameters for cathode and cell degradation. Unexpected high degradation rates were estimated at 750°C. Limited influence of the type of cathode on long-term behavior of cells was found; LSF/SDC cathodes exhibited, however, higher long-term stability.