The pronounced volatility of elemental mercury (Hg-0) and some of its compounds, coupled with their extreme toxicity, makes these substances extremely hazardous. Conversion of Hg-0 to HgO would significantly enhance mercury removal from flue gases. This investigation is focused on studying the effect of some of the constituents such as O-2, H2O, CO2, and NOx present in flue gases on elemental mercury oxidation in a dielectric barrier discharge (DBD) reactor. The results show that Hg vapors (6 ppbv) in a stream of 0.1% O-2 and N-2 are effectively oxidized at the energy density of up to 114 J/L. Hg conversion of over 80% is achieved when present in a gas mixture of 8% O-2, 2% H2O, and 10% CO2 in N-2 balance. The presence of NOx enhanced mercury oxidation in the DBD reactor. The oxidation chemistry is discussed. Studies show that Hg can be simultaneously removed along with the other two major pollutants, NOx and SO2, in one DBD reactor followed by a wet scrubber system. This avoids the need of three techniques for the removal of major gaseous pollutants from coal-fired power plants.