Abstract: An improved, essentially pollution-free incinerator for waste materials is provided which includes vertically stacked, separately fired primary and secondary combustion chambers and central, cooperating, apertured partition and baffle structure serving to assure complete burning of the waste materials and removal of particulate solids prior to discharge thereof to the atmosphere. In preferred forms, the central, chamber-defining partition includes a plurality of circumferentially spaced, peripheral apertures, while the baffle structure is in the form of an annular, peripheral shoulder formed on the inner wall surface of the secondary chamber above the partition apertures. The primary chamber also includes a waste material inlet and a burner system for igniting the waste materials, while the secondary chamber has tangentially disposed air and fuel inlets for creating a whirling flow pattern to assure essentially complete high temperature burning of the waste materials.