There is disclosed a method and apparatus for waste disposal by hydraulic embedment in a subterranean formation. A method in accordance with the present invention comprises the steps of drilling into stable geologic formations thousands of feet below ground, fracturing those formations, pumping a mixture of hazardous waste in solid, liquid, or sludge form and a selected transport medium into the fractured formations, and preventing migration of the waste. Although a suitable transport medium can be selected based on a number of factors, transport media selected in accordance with one aspect of the present invention prevent migration of the waste by reacting chemically or to either heat or pressure or both to become highly viscous or solid. In other aspects of the present invention, the method prevents waste migration by either pumping a fluid for sealing the fractured underground formation before the mixture is pumped or encapsulating the waste prior to mixture with the transport medium and injection into the fractured formation. Apparatus for carrying out the method is also disclosed.