In this work, different procedures, namely carbonate coprecipitation and modified solid–solid diffusion, were used to prepare hexaaluminate samples, unsupported or supported onto θ-Al 2 O 3 . These samples were used as catalyst for the methane total oxidation as synthesized or after impregnation of 1wt% Pd. It was observed that the modified solid–solid diffusion procedure is an efficient method to obtain the hexaaluminate structure. At a theoretical ratio x of hexaaluminate onto Al 2 O 3 less than 0.6 (xLa 0.2 Sr 0.3 Ba 0.5 MnAl 11 O 19 +(1−x)·Al 2 O 3 , with x=0.25, 0.60), samples with high specific surface area and θ-Al 2 O 3 structure are then obtained. Large differences in catalytic activity can be observed among the series of sample synthesized. All the pure oxide samples (i.e. without palladium) present low catalytic activity for methane total oxidation compared to a reference Pd/Al 2 O 3 catalyst. The highest activity was obtained for the samples presenting a θ-Al 2 O 3 structure (with x=0.60) and a high surface area. Impregnation of 1wt% palladium resulted in an increase in catalytic activity, for all the solids synthesized in this work. Even if the lowest light-off temperature was obtained on the reference sample, similar methane conversions at high temperature (700°C) were obtained on the stabilized θ-Al 2 O 3 solids (x=0.25, 0.60). Moreover, the reference sample is found to strongly deactivate with reaction time at the temperature of test (700°C), due to a progressive reduction of the PdO x active phase into the less active Pd° phase, whereas excellent stabilities in reaction were obtained on the pure and palladium-doped hexaaluminate and supported θ-Al 2 O 3 samples. This clearly showed the beneficial effect of the support for the stabilization of the PdO x active phase at high reaction temperature. These properties are discussed in term of oxygen transfer from the support to the palladium particle. Oxygen transfer is directly related to the Mn 3+ /Mn 2+ redox properties (in the case of the hexaaluminate and stabilized θ-Al 2 O 3 samples), that allows a fast reoxidation of the metal palladium sites since palladium sites reoxidation cannot occur directly by gaseous dioxygen adsorption and dissociation on the surface.