This book highlights on the co-firing of MSW in a fluidised bed combustor in terms of combustion efficiency and characteristics to assess the potential advantages offered by fluidised bed combustors over conventional methods of burning. The influence of various combustor operation parameters on the combustion efficiency and characteristics is determined. However, wastes are variable in nature, the combustion conditions suitable for one particular type of waste may not be so for another type. Hence the combustion efficiencies and compatibility of different wastes in a fluidised bed combustor operating under given sets of conditions is one area of investigation. A comparison of the experimental results obtained from the combustion of coal with co-firing waste with coal under equivalent conditions is made and the effect of the combustion characteristics of co-firing waste with coal is also investigated. Co-firing in FBC demonstrates the capability of supplement either MSW or other high moisture content wastes efficiently in existing coal-fired boilers with minimum modification.