Abstract: An infant crib in which the mattress is mounted on the frame in a secure position from which the mattress cannot be dislodged by an upward force beneath the mattress. A support panel has a plurality of straps affixed thereto which are of sufficient length to wrap around the surrounding rails or frame members of the crib and to be removably secured such as by Velcro fasteners. The mattress is placed on top of the thus secured panel. The fasteners are of sufficient strength such that when the fasteners are engaged the crib support panel can withstand a force from below the mounted panel of at least 224 pounds to meet safety standards and to prevent unintended dislocation of the crib mattress from its operative disposition. The invention can be embodied in a permanent crib structure or in a portable crib structure. The invention can also be embodied in a playpen or other infant furniture in which a mattress is to be secured.