Municipal solid waste management is a complex system with a variety of choices concerning source separation and alternative treatment/disposal options. A computer model which assesses life-cycle energy consumption, life-cycle emission of carbon dioxide, and cost was developed as a decision making tool for waste management systems. Waste streams in the system are modeled with twenty-eight waste components, the sub-system facilities are designed according to resulted waste streams, and only a minimal number of user-inputs are required for the simulation. The model has flexibility for the future changes in waste management options.