A steerable infusion guidewire having a deflectable distal tip which comprises a longitudinal hypotube and an interlocking spring coil which carry an infusion tube which is attached to the distal end of the hypotube and also includes a longitudinally movable deflection member which is attached to the distal end of the spring coil and a tip retaining member which extends from the distal end of the hypotube to the distal end of the spring coil for providing very precise deflection of the distal tip of the guidewire.