The decomposition of trichloroethylene (TCE) by hydrogen over Co/gamma-Al2O3 and Ni/gamma-Al2O3 catalysts under microwave heating was studied. The comparison between the catalytic activity in the microwave heating mode and that in the conventional thermal mode demonstrated that the microwave heating could greatly reduce the reaction temperature, accelerate the TCE decomposition speed and improve the TCE decomposition ratio. The results suggest that the microwave heating has a novel effect in the decomposition of TCE. (C) 2004 Elsevier B.V. All rights reserved.