A cellular cushion has a flexible base and flexible cells projecting outwardly from the base. The cells, which are formed from an elastomeric material and contain a gas such as air, are organized into longitudinal and transverse rows, and webs within the base separate the cells of adjacent rows. At least some of the cells are sealed in the sense that their interiors are totally isolated from all other cells and from the surrounding atmosphere. The cushion may also contain a zone of cells which are interconnected in the sense that their interiors are in communication along the webs of the base.