In this paper, low temperature CO oxidation over iron-cobalt mixed oxide nanocatalysts with different Co/Fe molar ratios was investigated. The nanocatalysts were prepared with a facile co-precipitation method. The prepared samples were characterized by X-ray diffraction (XRD), N-2 adsorption (BET), temperature programmed reduction (TPR), Thermal gravimetric and differential thermal analyses (TGA/DTA) and Transmission electron microscopy (TEM) techniques. The BET results revealed that the samples have a mesoporous structure and decreasing in Co/Fe molar ratio shifted the pore size distributions to smaller values. The TEM analysis showed a nanostructure for all samples with crystallite sizes smaller than 20 nm. The pure cobalt nanocatalyst showed uniform hexagonal closed packed structure. The catalytic results showed that the addition of Co to iron oxide even in small amount has a dramatic effect on increasing CO conversion at lower temperatures. The results indicated that the stability of catalysts was affected by reaction temperature, O-2/CO ratio and CO concentration in feed composition. The results showed that increase in reaction temperature increased the stability of catalyst. (C) 2012 Elsevier B.V. All rights reserved.