The high cost of a currently available selective catalytic reduction (SCR) process is driving R&D efforts toward finding alternative technologies to remediate NO emissions from utility boilers. A hybrid plasma-catalyst (P-C) system is investigated for NO., removal. The plasma (dielectric barrier discharge) and SCR techniques are each studied for the reduction of NOx for comparative purposes. gamma-Al2O3 is used as a catalyst in the hybrid P-C system. The hybrid P-C experiments show effective NOx removal compared to the results obtained from either plasma or SCR experiments. NOx removal by the P-C system is about 15% higher compared to that by the SCR alone when 1000-3000 ppm of methane or ethylene is added to the inlet gas stream. The hybrid P-C system has the potential to be successfully used for the removal of NOx from utility boiler flue gases and diesel exhausts.