Abstract: A mattress system for use in cribs or beds for small infants or adolescent children is constructed of a base and a sleeping recess defined by side walls, a head wall, a foot wall, and a floor. The mattress is constructed of a foam material which is air permeable. The mattress including the side, head, foot walls and floor of the recess, are enclosed in a removable cover. The floor of the recess is covered by a detachable vinyl panel formed as part of the cover and having hook or loop type strips. A second floor cover in the form of a detachable sheet, having mating hook or loop style patches which engage their opposite counterpart on the vinyl panel. An accessory panel is constructed having the dimensions of the recess to fill the recess and convert the specialty mattress into a conventional mattress.