The decomposition of chlorofluorocarbons (CFCs) in the presence of water was examined over a variety of solid acid catalysts. More than 40% of the conversion of CFC was observed on HY zeolite, H-mordenite, H-ZSM-5, gamma-Al2O3, and SiO2-TiO2 catalysts, and the selectivity to CO and CO2 was nearly 100% except on gamma-Al2O3. Although the H-mordenite had the highest activity among the tested catalysts, it was gradually deactivated during the reaction due to the elimination of Al atoms from the zeolite framework. A good relationship was found between the reactivity on H-mordenite and the bond energy of C-Cl in compounds of CCl4, CCl3F, CCl2F2, and CClF3, suggesting that the rate controlling step was the cleavage of the C-Cl bond.