The microwave-assisted reduction of NO by methane in the presence of oxygen over Co-NaZSM-5, and H-ZSM-5 catalysts was studied. We demonstrated that microwave radiation at 2.45 GHz significantly enhances the catalytic conversion of NO to N-2. High conversions (>70%) of NO were achieved over both Co-NaZSM-5 and Co-HZSM-5 zeolite catalysts at temperatures 250-400 degrees C. Under similar conditions, thermal runs failed to show significant conversion of either NO or methane.