The paper describes the use of solidification/stabilization (S/S) technology for treating hazardous waste. Although it has been used for 20 or more years to treat U.S. industrial waste, the banning of selected untreated waste to the land has resulted in an increased interest in the technology. S/S involves the addition of binders (e.g., portland cement, lime, fly ash, etc.) to the waste to alter the waste form and decrease the mobility of the pollutants. Advantages and disadvantages of S/S vary with the process, the binders, the waste, site conditions and other factors. As an alternative treatment technology, S/S best potential use is to treat wastes that are banned from land disposal. However, there are important factors which will affect the use of S/S. These include waste characteristics, process types, S/S waste treatment and management objectives, regulatory requirements, and economics. These and other specific factors must be carefully considered to ensure acceptable S/S performance.