Highly durable catalyst for high temperature methanol steam reforming is required for a compact hydrogen processor. Deactivation of a coprecipitated Cu/ZnO/ZrO2 catalyst modified with In2O3 is very gradual even in the high temperature methanol steam reforming mainly at 500 degrees C, but the initial activity is considerably low. Addition of Y2O3 to Cu/ZnO/ZrO2/In2O3 increases its initial activity due to the higher Cu surface amount, while the activity comes gradually close to that for the catalyst without Y2O3 during the reaction. Coprecipitation of Cu/ZnO/ZrO2/Y2O3/In2O3 on a zirconia support triply increases the overall activity by keeping the durability while the amount of the coprecipitated portion is a half of that without the support. On the composite catalyst, sintering of Cu particles is suppressed. The surface Cu amount is similar to that without the support, but the Cu surface activity is much higher probably because of the small Cu particle size. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.