The present review describes the factors affecting the composition of landfill leachate and it has been prepared on the basis of extensive survey of literatures. The main objective of this study was to explore the knowledge on
various factors that affect the composition of municipal solid waste landfill leachate. The composition of leachate greatly depends on the age of the landfill and also on the process occurring in that age. The landfill cannot fill at a time and therefore contains many cells and section and experiences different pressure condition, this might occur different phase simultaneously within one landfill. Similarly, there are many factors which may affect the composition of municipal solid waste landfill leachate. Some of the factors are for e.g. waste composition, depth of waste, moisture content, available oxygen, temperature, co-disposal with inclinator ash, waste processing, age of landfill, and toxicity. These factors are described in detail in the current review. In general, variations in leachate quality with age should be expected throughout the landfill life because of stabilization of organic matter in the long run.