This paper describes an integrated analytical framework that captures the major economic, engineering, geographic, and social factors affecting the internal (direct) cost of abyssal ocean waste disposal. We develop cost estimates for the disposal of sewage sludge and municipal incinerator ash via a deep ocean waste delivery system concept developed by Oceaneering Technologies. Our study focuses on five metropolitan areas and proposed abyssal study sites identified by the Naval Research Laboratory. The unit cost of isolating a given waste stream in the abyssal ocean is shown to depend on many factors, including the size of the region from which waste is brought to the transshipment port, the distribution of waste-generating centers within the region, the technology used for transporting the waste to the seafloor, and the distance of the abyssal site from the port. Our findings indicate that the internal cost of abyssal ocean waste isolation is about $43 per ton for sludge and ash from the New York metropolitan area. If associated external costs are not significantly higher, and the marine transport concepts do not prove to be significantly more expensive than anticipated, the abyssal ocean option may be competitive with present land-based disposal costs in New York City. The abyssal ocean option may be less competitive in other metropolitan areas because of their more limited waste volumes.