tThe catalytic oxidation of CO into CO2on mesoporous Fe–Co mixed oxide nanocatalystsat low temperature was carried out. The catalysts with different ratios of Co3O4(1–30 wt.%)were prepared by a simple co-precipitation method. The original and calcined catalysts werecharacterized by TG, DTA, XRD, TEM, VSM, N2sorption analysis, surface chemisorbed oxy-gen and dc electrical conductivity measurements. The results revealed that the addition ofCo3O4to Fe2O3monotonically increases the amount of surface chemisorbed oxygen, elec-trical conductivity and catalytic activity of the nanocatalysts. The role of the active redoxsites established in these nanocatalysts such as, Co3+/Co2+, Fe3+/Fe2+and Co3+/Fe2+whichare responsible for such modification was discussed. The magnetic studies indicated thatthe Fe–Co mixed oxide nanocatalysts exhibited ferromagnetic nature and the catalyst con-taining 30 wt.% Co3O4calcined at 600◦C possessed the highest saturation magnetization(Ms= 51.5 emu g−1). In addition the kinetic data illustrated that, the activation energy val-ues of CO oxidation gradually decreased with increasing of Co3O4content. Moreover, thecatalytic behavior under different atmospheres during calcination was also studied.