The rate of microwave-induced regeneration of nitrogen oxides (NOx)-saturated char was studied. A small amount of NOx-saturated char sample was placed in the microwave field, and its weight was measured as a function of time by a digital balance. The weight loss data were used to calculate the activation energy of C-NO reaction under microwave radiation. The experimental results showed significant surface complex formation from the C-NOx reaction during the regeneration of NOx-saturated char. An increase of power input not only lowered the amount of surface complexes but also enhanced the regeneration rate. When the input power was >300 W, the regeneration was actually completed within 1 min. The activation energy of the microwave-induced C-NO reaction was estimated as 17 kJ/mol, much less than those obtained by others using conventional heating (63-68 kJ/mol).