Abstract: A self-cleaning cat litter box has the ability to automatically filter and separate clumped soiled litter and fecal matter from clean litter. The apparatus includes a rotatable drum, a spiral filter within the drum, and a stationary back plate. The drawn has front and back walls, and the front wall has a front opening which permits access and egress by a domestic pet. The back wall has a first opening for both the removal of soiled litter and the addition of clean litter. The spiral filter is slotted, and is mounted on the inner surface of the drum. The stationary back plate is parallel to the plane of the back wall and has a second opening which permits the passage of soiled litter away from the drum, and a third opening to permit the passage of clean litter into the drum. The drum is rotated by a suitable drive, which can be electively actuated by a switch.