Abstract: A medical coupling for a cannulae includes a female member (1) with a body providing a hub (4) defining a socket (11), a valve section (5) with a valve actuator (15) slidable on the body, an internally splined sleeve (44) movable with the valve actuator, and a finger gripping section (5), and a male member (2) including a spiget (20) for engagement in the socket (11), a cap (21) with a screw thread for engagement with a thread (10) on the hub (4), and external splines (45) on the cap. When the spigot is inserted into the socket (11), the cap (21) is rotated onto the screw thread (10to hold them against being pulled apart, and the valve actuator is displaced to open the valve and to bring the splined sleeve (44) into locking engagement with the cap (31).