China produces roughly half of the world's cement, a large share of which is made inenergy inefficient, highly polluting kilns. The cement industry is a major source of multiple airpollutants, among them dioxins, mercury, particulate matter and greenhouse gas emissions. In2005, just over one billion tons of cement was produced in China and cement demand willcontinue to be high in the near future as development goals are pursued.In the kiln, production of clinker, the main ingredient of cement, consumes about 80% ofthe energy used at a cement plant. Clinkering is also the source of almost all carbon dioxide andtoxic emissions produced from cement manufacture. This paper examines measures that can beused to retrofit or to replace older, inefficient Chinese cement kilns to improve their energyefficiency, reduce pollution and maximize the industry's economic performance and output. Weprovide costs, savings and payback periods upon implementation for case studies around theworld, and where possible, specifically in China. Fourteen of the technologies and measuresexamined have simple payback periods of three years or less.