Manganese oxide-supported gold (Au/MnOx) catalysts have been prepared and tested for low-temperature (< 100 degrees) carbon monoxide oxidation in stoichiometric mixtures of carbon monoxide and oxygen containing no carbon dioxide in the feed gas. Even with no pretreatment these catalysts are superior to the best, pretreated platinized tin oxide (Pt/SnOx) catalysts under the conditions tested. The very small decay observed for Au/MnOx catalysts is mostly due to carbon dioxide retention. The optimum gold content has been determined to be 10 at.-% of the manganese content, and a lithium promotor results in improved catalytic behavior over K- or Na-promoted Au/MnOx catalysts for the conditions examined in this study.