The relationships between the cathode performance, the La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF)/Ag ratios, and the porosity of the LSCF-Ag cermet cathode were investigated. The Ag fractions in the LSCF-Ag powder were changed from 20 to 80 wt %. The microstructures of the porous LSCF-Ag cermet cathodes were observed using a scanning electron microscope, and the area specific resistance of the cathodes was measured by the two-probe ac impedance method. The LSCF-Ag cermet cathodes with different Ag fractions annealed at 750 degrees C for 3 h had the optimum microstructure and the lowest Rp when the Ag fraction in the LSCF-Ag cermet cathodes was 40 or 50 wt %, and the LSCF-Ag cermet cathode including 50 wt % Ag had a sufficient porosity without the poly(methyl methacrylate).