A catheter assembly (2) comprising a catheter hub (4) a hollow tubular catheter (10), the catheter being connected at its proximal end to the distal end of the catheter hub a needle (30) having a needle tip (36) a hollow extension tube (62), the extension tube being connected at its distal end to the catheter hub between the proximal and distal ends thereof a valve assembly (70) disposed within the chamber of the catheter hub, the valve assembly comprising a first valve member (72) closing the distal end of the extension tube and openable under the action of a pressurised fluid within the extension tube and a second valve member (74) preventing the flow of fluid through the chamber to or from the proximal end of the catheter hub. A needle guard assembly (102) is also provided.
