Apparatus for treating infectious wastes from hospitals, medical clinics or the like integrates sterilizing, fragmentizing and compaction steps within a single waste processor. Wastes which are deposited in a sterilization chamber are made non-infectious by exposure to pressurized steam. An outflow of wastes from the sterilization chamber is fed through one or more on-line shredders or the like and then into a compactor which compresses the processed material into a transportable container that may be hauled to a dump site.