In this paper, catalytic oxidation of CO over perovskite-type oxides LaMn1-xBxO3 (B = Cu, Fe and x = 0, 0.1, 0.3, 0.5) were investigated. The perovskite catalysts were synthesized by sol-gel method and characterized by XRD, BET, H-2-TPR, XPS and SEM. XRD patterns showed that the samples are single-phase perovskite. By introduction of Cu and Fe in the structure, Specific surface area of LaMnO3 was decreased, but the reducibility and oxygen vacancy were increased. The synthesized perovskite catalysts show high activity for the CO oxidation. Substitution of Mn by Cu and Fe enhanced the catalytic activity. The cu-containing perovskites showed a higher activity in CO oxidation compared with Fe-containing perovskites. The LaMn0.7Cu0.3O3 perovskite showed the highest activity among the synthesized perovskites (T50 and T90 % of 110 and 142 A degrees C). The excellent activity of LaMn0.7B0.3O3 was associated to reducibility at low temperature, more oxygen vacancies and synergistic effect between Cu and Mn. The apparent activation energies were obtained and LaMn0.7Cu0.3O3 as the most active catalyst, has the least activation energy compared with other synthesized catalysts. [GRAPHICS]