Methanol decomposition to hydrogen and carbon monoxide can be effectively catalyzed at 160-220 degreesC over palladium supported on mesoporous zirconium oxide by the deposition-precipitation method. The electronic state and the particle size of palladium in the catalyst are very similar to those of palladium supported on non-porous zirconium oxide, but the palladium surface area of the former sample is smaller than that of the latter. However, the activity of the mesoporous catalyst is significantly higher than that of the non-porous catalyst, implying a promotional effect of the mesoporous structure.