A double seat valve having a seat for cooperation with two valve disks which are linearly adjustable relative to each other and together relative with respect to the seat, for a seat valve function and a sliding valve function, each of the valve disks containing a ring seal with an elastic sealing ring in a ring groove, both sealing rings being manufactured with the same shapes and dimensions, each sealing ring being positioned in the ring groove with a backup ring, and both sealing rings being arranged in rotational positions differing with respect to the respective sealing function relative to the direction of adjustment of the valve disks.