Аннотация:Abstract: The activity of LaMO3, where M=Cr, Mn, Co, perovskite-type complex oxides in oxygen diffusion and catalytic processes was investigated. For sample preparation freeze-drying technique was used and dynamic thermal isotope exchange method was used to study exchange reaction between O-18 from the gas phase and O-16 from the samples synthesized, and to investigate the methane catalytic oxidation reaction. The results obtained allowed tp indicate temperature intervals of different ty es of reaction taking place and that LaCrO3 is far less active in mentioned reactions than LaCoO3 and LaMn