The performance of Au/MnOx and Pt/SnOx catalysts for low-temperature (<100 degrees C) CO oxidation under stoichiometric conditions has been examined for the case where 8% or 16% CO2 is added to the feed gas. High concentrations of CO2 in the reaction gas mixture adversely affect the behavior of these catalysts due to CO2 retention at their surfaces. The magnitude of this detrimental effect can be reduced by adding an Fe promotor to both types of catalysts and optimizing various preparative and pretreatment variables.