A mesoporous oxide composition includes, other than oxygen, a major amount of aluminum and lesser amounts of phosphorus and at least one rare earth element. The compositions have high surface area and excellent thermal and hydrothermal stability, with a relatively narrow pore size distribution in the mesoporous range. These compositions may be prepared by a hydrothermal co-precipitation method using an organic templating agent. These mesoporous oxide compositions may be used as catalysts or as supports for catalysts, for example, in a fluid catalytic cracking process.