Abstract: An underlayment material is disclosed for use as an underlayment in a non-textile flooring system. The underlayment material comprises a thin, flexible layer of polyurethane foam and a thin, flexible substrate layer bonded to one side of the layer of polyurethane foam. In a preferred embodiment, the underlayment material is a mechanically frothed polyurethane foam. In another preferred embodiment, the substrate layer is a layer of non-woven spun bonded polyester fibers. In another preferred embodiment, the underlayment material has a thickness of between about 0.05 and 0.125 inches, and most preferably, about 0.085 inches. In still another preferred embodiment, the foam has a fine cell structure and a density of between 10 and 30 pounds per cubic foot, and most preferably about 20 pounds per cubic foot. In still another preferred embodiment, the foam has a compression set of between about 5% and 25%, and most preferably about 10%.