Abstract: A guidewire and method of using same for tracking an indwelling device such as a catheter previously positioned within a body lumen. The guidewire includes an elongate flexible body shaft having proximal and distal ends, and a tracking member disposed at the region of the distal end. The tracking member defines an opening passable over the shaft of the indwelling device. During use, the tracking member is slid along the indwelling device toward its distal end to enable the guidewire to track the path of the indwelling device. The indwelling device then may be withdrawn from the patient's body lumen and an over-the-wire catheter may be threaded onto and advanced along the guidewire into the patient's body lumen. The tracking member is retractable within and removable from the guidewire. The invention is useful particularly in catheterization procedures where it is desired to exchange an over-the-wire catheter for a catheter having a fixed or integral guidewire.