The kinetics of reduction in H 2 of the perovskite LaMnO 3 and also the kinetics of O 2 adsorption on this oxide were studied. The reduction process starts at 755 K; up to 950 K the reduction rate is low because of the slowness of nuclei formation and growth (nucleation). Once reduced nuclei are formed, the reduction process occurs at a higher rate (950–1050 K). At 1100 K a stable reduced state of ca. le − per molecule, accompanied by the disappearance of the perovskite structure and formation of La 2O 3 and MnO, was reached. The reduction isotherms (873–1013 K), of sigmoidal form are typical of a reduction process controlled by formation and growth of reduction nuclei on the surface. An apparent activation energy of reduction of ca. 225 kJ mol −1 was found. The kinetics of O 2 adsorption showed (by means of plots b( dq d ln t) vs at) an Elovichian zone preceded (followed) by pre- and post-Elovichian regions. The results were fitted to a model of adsorption on a heterogeneous surface developed by M. Ungarish and C. Aharoni ( J. Chem. Soc. Faraday Trans. 1 79, 119, 1983). The isobar of adsorption showed, in the range 350–700 K, two different activated processes which were associated to dissociative adsorption of oxygen (350–525 K) and incorporation of oxygen into the oxide lattice (above 600 K). A parallellism among oxygen adsorption, reducibility, and catalytic activity for total oxidation on LaMeO 3 oxides was found.