A method of percutaneous introduction of a catheter into a vessel. The vessel is located and a needle is inserted. Once a good blood flow is obtained, a wire is threaded through the needle well into the vessel; the needle is then removed and the catheter threaded over the wire into the vessel. The wire assists in inserting the catheter and guiding it into the appropriate vessel. Once the catheter is positioned in the desired intravascular area, the wire is removed. Sterile technique is imperative.