The invention concerns a connector for connecting respiratory ducts together such that they are placed in fluid communication. The connector comprises a first conduit having a female connector end and a second conduit having a male connector end adapted to be received within the female connector end of the first conduit such that the male and female connector ends form a common conduit having an inner surface formed at least in part by the male connector end. The male connector has a retaining formation which is adapted to abut a corresponding formation of the female connector so as to resist separation of the first and second conduits while permitting relative rotation there-between when connected. The inner surface of the male connector may comprise a gas washed surface in use. The engagement formation is preferably a recessed area of the female connector, which may be generally annular in shape. In one embodiment, the member(s) may comprise a valve seat. The invention also concerns a breathing circuit comprising the connector.
