A litter box cleaning system includes an upright cabinet with a litter pan pivotally mounted in the upper end to move between a horizontal use position and a tilted dump position. A slot is formed in the pan front wall to dispense litter and waste material when the rearward end of the pan is lifted to the dump position. A waste receptacle in the cabinet is positioned below the pan slot such that litter and waste from the pan free-fall into the receptacle for storage and removal. In a second embodiment of the invention, the front wall of the pan is spaced away from the cabinet front wall, and a flap is hinged to the front of the pan to block litter material from falling from the slot.