Abstract: In accordance with the instant invention, there is provided a mattress topper which is designed to be placed atop a mattress and/or box spring combination. In the preferred arrangement, the topper consists of a sandwich of three layers. The outer layers are preferably comprised of open cell foam of a thickness about equal to one inch or so. The inner layer is an impermeable central liner which is preferably made of a material such as plastic. The function of the central liner is to prevent the migration of fluids from one side of the topper to the other. Thus, although the foam upper layer is very absorbent, an inadvertent spill or other deposit of moisture will be blocked in its migration through the topper by the central waterproof member, thereby protecting both the lower member and the mattress below from exposure to the moisture. In a preferred embodiment, the inner layer is comprised of a foam stiffener core encased by an impermeable wrapping.