Abstract: A tubing adaptor of unitary plastics construction is assembled with an endotracheal or other medico-surgical tube for coupling the tube to a connector or tubing of larger diameter in a gas circuit. The adaptor has a tubular stem which closely fits into the tube and which extends from, and opens through, the base of the cup-shape body portion. The cup-shape body portion is for insertion in the passageway of larger diameter to establish the coupling, and the tubular stem is turned back on itself at its open end remote from the base so as to provide an external circumferential claw or lip that is splayed outwardly away from the open end so as to engage with the inside of the tube to restrain withdrawal of the stem from the tube. The claw may be formed by a step which involves the application of force uniformly around the whole circumference of the open end of the stem after that end has been splayed outwardly, against an inclined circumferential shoulder of a spigot.