Abstract: A mattress for small children has a removable foam insert which fits in an aperture cut in the head portion of a foam mattress body. The insert has a plurality of perforations extending from its top face to its bottom face which reduce the risk of suffocation, the perforations being grouped towards the head of the mattress for optimum positioning beneath the child's head. To ensure that a replacement insert, when the former insert is soiled and requires washing, is fitted in the correct orientation, each insert has a key portion projecting from one edge for interlocking with a correspondingly shaped recess in a side wall of the aperture.