Elevated temperatures in various landfill types can produce obnoxious odors, toxic gases, and aggressive leachates, as well as damage landfill infrastructure. They also can result in expensive remedial measures and warrant permanent closure of the facility. This presentation will discuss mechanisms that can lead to elevated temperatures in landfills using recent case histories and present associated trends in gas composition, leachate collection, settlement, and slope movement. In general, landfill gas composition changes from predominantly methane (50-60% v/v) and carbon dioxide (40-55% v/v) to a composition of carbon dioxide (60-80% v/v), hydrogen (10-35% v/v), and carbon monoxide (> 1,500 ppmv) as temperatures elevate. As waste temperatures increase, gas and leachate pressures also increase, resulting in odors, leachate outbreaks, and possible slope instability. Based on observed management, operation, and maintenance of elevated temperature facilities, various operational techniques will be presented for isolating and containing the elevated temperatures.