A coaxial guidewire for use in accessing smaller vessels within a patients body, consists of an inner core wire and an outer hollow wire. The distal end of the inner core wire tapers and supports a spring coil. The core wire, including the spring coil, fits within a 25-gauge needle that is used to locate an artery of the patient. When the needle is removed over the inner core wire, the outer hollow wire, having a distal end that tapers to the outer diameter of the spring coil, fits over the inner wire and is advanced until the distal end of the outer wire meets the spring coil of the core wire. A dilator and introducer sheath combination may then be fed over the assembled coaxial guidewire. When the distal end of the sheath is in the desired position, the dilator and the coaxial guidewire are removed.
