This review describes (inorganic-organic hybrid) mesoporous silica and alumina preparation with a uniform pore structure, as well as some environmental applications. Functional organic groups can be incorporated in the mesoporous materials by grafting, co-condensation and imprinting methods, and these groups affect the hydrophilicity/hydrophobicity of the surface and its affinity for metal ions. Applications of mesoporous materials are highlighted, including catalysts for hydrogenation and hydrodechlorinaton, and the sorption of heavy metal ions, anions, and organics. Because of their controlled porosity and ultrahigh surface-to-volume ratios, these materials show superior catalytic activity and higher adsorption capacities than amorphous or non-porousmaterials.