A review of the municipal solid waste (MSW) management and planning literature reveals the growing number and complexity of the available mathematical models. A technical survey of practising waste management professionals indicated a general interest in, but lack of practical applications of, mathematical modelling techniques. The creation of knowledge-based systems to interface with individual MSW management and planning models, or assist with model selection and integration is proposed. As a means of demonstrating the validity of the suggested decision support approach, a prototype decision support system was developed to assist with the preliminary planning of MSW management systems. This planning tool combines knowledge-based system components with spreadsheet, optimization and stimulation models to assist with: waste forecasting; technology evaluation; recycling and composting programme design; facility sizing; location and investment timing; waste allocation; and MSW management system analysis using stimulation. A case study application of the planning tool is described.