A self-cleaning pet litter box has a conveyor to incrementally transport clumped litter material and solid pet waste to a waste receptacle. The conveyor has one end configured to extend into a pet litter container of the self-cleaning litter box and an opposite exit end. The conveyor is configured for reciprocating movement to lift the clumped litter material and solid pet waste from below, transport it some distance along the conveyor, place the material down again, return to its original position, and repeat the motion again to incrementally move the material along the conveyor toward the exit end for subsequent disposal.