Abstract: The present invention comprises a shim formed from a circular disc that transitions uniformly in thickness from a first point having a first thickness to a second point having a second thickness on the opposite side of the shim from the first point. The shim further comprises a central opening formed therethrough to allow communication between the toilet drain opening and the opening of the closet flange. The shim additional includes one or more arcuate slots formed therethrough for permitting hold-down bolts to be attached through the shim and into a closet flange positioned below the shim.