Abstract: An upholstered body, especially mattress, with a spring core which is provided with at least one cover plate of elastic foam material, and has on at least two opposite sides thereof inwardly of the plate respectively arranged a marginal body member of elastic foam material. In the transition area between the cover plate or cover plates and the marginal body members on at least two oppositely located sides of the upholstered body, there are provided bend-elastic bar-shaped stiffening bodies which consist substantially of compacted synthetic foam material, preferably of the same type the marginal body members are made of and preferably integral therewith. These stiffening members are located at the inside of the adjacent cover plate. Interposed between the at least one cover plate and the adjacent ends of the springs is an intermediate layer having its marginal areas connected to the stiffening bodies.