A tracheostomy tube assembly comprises a tracheostomy tube (2), a fitting (4) to be mounted on the end of the tracheostomy tube (2), having a bore (6) in which teh end (8) of the tracheostomy tube (2) can be received, a sealing memeber (10) which can be located between the outer surface of the tracheostomy tube (2) adn the inner surface of the bore (6) in the fitting (4), and means (12) for urging the sealing member against the outer surface of teh tracheostomy tube to form a seal between the fitting (4) and the tracheostomy tube (2). The assembly allows a sealed connection to be made to the end of the tracheostomy tube (2), so that a filter (20, 32) or a valve (34) (for example to assist in speech) can be fitted over a