This paper reviews and analyzes the major recent North American studies that have compared on an environmental basis the major options used to manage the materials that comprise municipal solid waste (MSW). The reviewed studies provide quantitative comparative information on one or more of the following environmental parameters: solid waste output, energy use, and releases of pollutants to the air and water. The review finds that all of the studies support the following conclusions: Systems based on recycled production plus recycling offer substantial system-wide or ＇＇life-cycle＇＇ environmental advantages over systems based on virgin production plus either incineration or landfilling, across all four parameters examined. Only when the material recovery or waste management activities are analyzed in isolation-which does not account for the system-wide consequences of choosing one system option over another-do the virgin material-based systems appear to offer advantages over recycled production plus recycling.