The Resource Conservation and Recovery Act (RCRA) of 1976 and its 1984 Hazardous and Solid Waste Amendments (HSWA) required the U.S. Environmental Protection Agency (EPA) to develop criteria and/or standards for the management, including land disposal and long-term containment, of hazardous and nonhazardous wastes that would be protective of human health and the environment. EPA has been conducting laboratory and field investigations to improve containment strategies that incorporate state-of-the-art materials and design alternatives. Geosynthetics, including flexible membrane liners (FMLs), geonets, geotextiles, and plastic pipe, are playing an increasing role as structural components of containment facilities. One must be mindful to utilize these relatively new materials in ways that will not exceed their design limitations. The paper will discuss factors important to the use of geosynthetic materials in the design and construction of the leachate collection system parts of the containment unit. Laboratory testing of these materials to assist in material selection is also briefly discussed.