Monolithic catalysts were prepared by washcoating an alumina sol and then im pregnating Cu Mn Ag mixed oxides onto cordierite substrates. The effects of the preparation parameters including the Ag/Cu/Mn ratio, the total amount of active phase and the loading of washcoat, and the reaction conditions, e. g., the space velocity and the oxygen/toluene ratio on the catalytic performance for the corn bustion of toluene were investigated. It is shown that the Cu Mn Ag oxides are very active for the combustion of toluene and that the highest catalytic activity is achieved over a monolithic catalyst containing 14. 7wt% of washcoat and 21. 2 wt % of active phase with a Ag/Cu/Mn molar ratio of 13. 8/43. 1/43. 1. It is also seen that the optimum catalyst has a good catalytic stability and exhibits an excellent activity not only at a rather high space velocity but also within a wide range of oxygen/toluene ratios.