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The aim of this work was to study the effect of cation-substitution on the reducibility of the perovskite, as well as the effect on the catalytic activity for the CH₄ oxidation reaction. Six perovskites (LaCoO₃, LaMnO₃, La_1−xSr_xMnO₃ (x=0.2, 0.4), and La_1−xCe_xMnO₃ (x=0.05, 0.1)) were synthesized by reactive grinding. The reducibility of the perovskite was studied by means of the oxygen storage capacity (OSC) measurement. OSC was performed at different temperatures on LaCoO₃ and LaMnO₃, in order to elucidate the different mechanisms of reduction involved at each temperature. The substituted samples showed that reduction profile is modified at high-substitution degrees; however, no differences were observed on the OSC values (amount of most active oxygen, calculated after one pulse of CO) between the pure lanthanum sample and the substituted ones. Tested in the CH₄ oxidation reaction, the LaCoO₃ …