A self-sealing catheter valve (1,19) includes a flexible tubular part (2) having a distal opening (6) and an opposite proximal opening (12), and a proximal valve part (5). The proximal valve part (5) has a curved self-sealing flexible diaphragm (7) disposed inside the flexible tubular part (2) and has a base perimeter (8) united with a circumferential wall (9) of the flexible tubular part (2). The curved self-sealing flexible diaphragm (7) has a concave surface (11) facing towards the proximal opening (12), and a convex surface (10) facing towards the distal opening (6), and a flexible diaphragm wall (14) of the curved self-sealing flexible diaphragm (7) has a traverse slit (15). The self-sealing catheter valve provides an efficient self-closing mechanism for a peripheral catheter assembly and constitutes an efficient barrier against potential contagious spread from the patient to the surrounding environment by blood born disease e.g. HIV, hepatitis and Ebola viruses.
