Abstract: A process and apparatus for disinfection of waste in autoclaves by the fractional vacuum-steam process having atmospheric pressure steam phases, followed by a superatmospheric steam phase and a evacuation of the autoclave following each steam phase. The autoclaves are transportable separate from the remaining apparatus. In the evacuation after an atmospheric pressure steam phase, removing the atmosphere from the autoclave by suction, condensing the steam fraction and separating it as liquid having approximately ambient temperature. During evacuation after a superatmospheric pressure steam phase, first eliminating condensate from the lowest part of the autoclave, and feeding it to waste water at approximately ambient temperature. Evacuation following an atmospheric pressure steam phase is from an upper region of the autoclave, the atmosphere being then freed from micro-organisms. The steam is removed and gas fractions are freed from odorous substances and discharged to the environment.