Abstract: A mattress for supporting an infant in a supine position during sleep. The inventive device includes a main cushion member having a central portion top wall tapering into an inclined head wall whereat a head of the infant can be positioned. A pair of lateral guides extend along opposed longitudinal sides of the central portion top wall for engaging lateral portions of the infant to preclude turning of the infant into a prone position. Breathing apertures are directed through both the inclined head wall of the main cushion member and the lateral guides to preclude blocking of the infants breathing during sleep, thereby reducing the incidence of infant sleeping death.