The purpose of this study is removal of elemental mercury in the form of HgS in the coal combustion flue gases with sorbents like activated carbon (AC) and iron sulfides. For coconut shell AC, Hg removal was enhanced by the presence of H2S in the absence or presence of low concentration of HCl, therefore it is thought that Hg was removed mainly in the form of HgS. At high concentration of HCl, Hg removal was enhanced greatly by forming Hg-Cl compounds (such as HgCl2 and/or Hg2Cl2). When FeS 2 was used as a sorbent, a high level of Hg removal (comparable to coconut shell AC) was observed even in the absence of H2S and in the presence of a high concentration of HCl. Re-structured FeS2 ores (by kneading) showed a very high level of Hg removal performance probably due to the exposure of large amount of sulfur (S) at the surface of the sorbents.