Abstract: A percutaneous vascular access portal for implantation in a patient for an extended period of time including a cannula having a skirt at its distal end for attaching to the wall of a blood vessel and a flange at the other end to be located near the patient's skin surface and to provide a stop for catheters that are inserted therein and accurately locate their distal ends and openings in the blood vessel. The portal is provided with an obturator to block flow through the cannula when the portal is not being used, the obturator fitting snugly and sealably within the cannula and allowing for no dead space within the cannula in which blood could stagnate.