The reactivity and mobility of the surface and lattice oxygen in a La1-xCaxFeO3-y system prepared via a ceramic route were studied by using CH4-TPR. While the middle-temperature (400-700degreesC) oxygen lattice mobility reaches maximum for samples with disordered anion vacancies, the high-temperature lattice oxygen flux appears to be controlled by a rapid transfer along disordered domain walls. In the high-temperature range, a high selectivity to syngas of methane oxidation by the lattice oxygen was achieved both for pure lanthanum ferrite and for samples with a microdomain structure.