Primary objectives in design of surface disposal fills for processed and raw oil shales are: (a) to insure long-term physical stability, and (b) to prevent surface runoff, surface erosion, and possible subsurface seepage from degrading the water quality of streams and ground water, it was concluded that the analysis and design of spent shale disposal fills should be based on sound geotechnical engineering principles, considerable experience, and good judgment. An understanding of the source of variability of spent shale materials and its effect on engineering properties is a first step in developing fill design. A second important step is the assessment of long-term changes in the properties of spent shale within a disposal fill. This assessment requires consideration of possible thermal, hydrochemical, and physical interactions within the fill and between the fill and site environment. The site environment is site-specific and depends on the geological, surface and subsurface hydrological, and geotechnical characteristics of the site. The variability of spent shale materials is a direct function of variations in mineral and chemical composition of the raw shale and of the processes applied. Current technology for the design and construction of spent shale disposal fills has not been proven by experience. A major problem is the large quantities of spent shale generated for surface disposal and the lack of available sites other than large gulches in the oil shale country of the western United States. Conceptual research fill designs developed in this study should be refined and constructed to provide needed information on in situ properties and long-term performance. Research fills planned by others should be augmented to obtain needed information, especially for codisposal of spent shales with treated waste water, raw shale fines, and process dust.