The effect of aluminum addition on the properties of lanthanum oxide was investigated in order to find new supports for catalytic purposes. Pure lanthanum oxide and aluminum-loaded lanthanum oxide were prepared by precipitation techniques and impregnation with nickel salt. The supports and the catalysts were characterized by several techniques and the catalysts were evaluated in methane steam reforming, an important commercial route to produce high purity hydrogen. The results showed that aluminum changed the properties of lanthana-supported nickel catalysts improving the activity in methane steam reforming and the selectivity to hydrogen. The aluminum-free catalyst showed low activity since the first hours of reaction. On the other hand, the aluminum-loaded catalyst showed high activity and selectivity to hydrogen, which increased even more during reaction. This finding can be explained in terms of the production of metallic nickel, from the nickel compounds in strong interaction with the support. Therefore, the most promising catalyst was the aluminum-loaded lanthana, which showed high activity, selectivity to hydrogen and stability under reaction conditions. (c) 2008 Elsevier B.V. All rights reserved.