Abstract: The disclosure relates to improvements in pneumatically inflatable seals for sliding doors. The seal is in the form of an elongated elastomeric tube disposed in a channel adjacent to the door frame. After closing of the door or doors, the seal is expanded by pneumatic pressure, tightly closing the space between the door and the channel. The invention is directed specifically to improvements in the construction and configuration of the sealing element, for improving sealing effectiveness in the region at the extremity or extremities of the sealing element. The improvement is realized by incorporating one or more longitudinally disposed, deformable sealing ribs, providing sealing contact between the inflatable seal and the door surface in a transition zone at the end of the tubular sealing element, where the element does not fully expand when subjected to internal fluid pressure.