A hyperthermia headgear liner is provided comprised of an insulative material constructed to minimize exposures to fibrous materials an remove any habitat for bacterial growth. The cap extends over a greater portion of a wearer's forehead, over the wearer's ears and behind the head to reach as far as the top of the cervical spine. Lining the upper portion of the inner shell are a plurality of linearly aligned pockets formed of an open weave of mesh fabric. Each individual pocket contains and secures a cooling element formed of a phase change material. The cooling elements are removable and replaceable and are positioned along the midline of the head covering in a manner that form fittingly curves with the contour of the wearers head.