The number and complexity of mathematical models to assist municipal solid waste management agencies in the planning of recycling programs are increasing. A survey of practising waste management professionals has indicated a general interest in mathematical modelling techniques to assist with decision-making, but there is a lack of practical applications of these techniques, particularly within the local and regional waste management agencies that are responsible for planning and implementing waste reduction and recycling measures. A prototype decision support system has been developed to assist with the preliminary planning of municipal solid waste composting and recycling programs and processing facilities. This prototype planning tool combines knowledge-based system components with spreadsheet models to assist with waste forecasting, technology evaluation, composting and recycling program design, and preliminary processing facility planning. The system was designed for use by local and regional solid waste management engineers and planners, and waste recycling coordinators. The prototype decision support system is considered to represent a reasonable, useful, and practical (with respect to data requirements and cost) planning tool. The knowledge bases, created for the prototype decision support system, represent the collection and organization of a significant amount of currently available expertise regarding composting and recycling program planning issues. Key words: municipal solid waste, waste management, recycling, composting, decision support systems.