Mercury and sulfur emissions from power plants is becoming increasingly an environmental concern. In this study, two Chinese coals from the Guizhou province and one Canadian coal from Alberta were selected to study the potential of thermal upgrading as mercury and sulfur emission control strategy prior to coal use. A low-temperature asher (LTA) and X-ray diffractometer (XRD) were used to characterize the occurrence of mercury and sulfur in coal. An experiment of mild thermal upgrading at different atmospheres was performed to explore the removal efficiencies of mercury before combustion. Our study shows that mercury is associated with different minerals in these coal samples. The correlation between mercury and sulfur is also investigated. Mercury was found to be removed effectively by mild thermal upgrading at 400 degrees C under a 4% O-2-N-2 atmosphere. An oxidizing atmosphere increased the removal of pyritic sulfur significantly at low temperatures. The mercury release rate was found to be higher under an oxidizing atmosphere than under a nitrogen atmosphere between 300 and 400 degrees C during mild thermal upgrading.