It is shown that the substitution of 5% ferroactive molybdenum cations for iron to the La0.6Sr0.4Co0.2Fe0.8O3 – δ (LSCF) structure leads to a considerable increase in the electric conductivity. Using the powder X-ray diffraction technique, the solubility limit of molybdenum in the structure of rhombohedral perovskite is found. It is noted that the transport characteristics of perovskite with the La0.6Sr0.4Co0.2Fe0.75Mo0.05O3 – δ (LSCFM5) composition are sufficient for using it as the cathode material in intermediate temperature solid oxide fuel cells (IT SOFCs).