Disclosed is a disposable introducer kit for the introduction of a catheter into small vessels such as the radial artery of a patient. The introducer assembly is contained in a sterile package and removed as an entire unit including needle, catheter, wire guide and wire guide feed device. The catheter is mounted on the introducer needle with the tip of the needle extending slightly beyond the tip of the catheter. A guide tube extends rearwardly from a hub on the back of the needle. The wire guide is mounted in the tube with a wire guide actuating handle projecting through an elongated slot in the side wall of the tubing. In use, the needle is first inserted into the lumen of the vessel. The spring wire guide is next advanced by means of the actuating handle as far as possible into the vessel. The catheter is then advanced forwardly to track the spring wire guide into the vessel to the desired position. Thereafter the spring wire guide, needle and feed tube assembly are all removed and the catheter connected to the desired equipment.