Abstract: A balloon catheter includes a one-piece shaft and a guidewire track for use of a guidewire that runs along an outer surface of the one-piece shaft adjacent to a longitudinal central axis of the one-piece shaft. The one-piece shaft has an inflation lumen formed therein. The one-piece shaft is formed to include a substantially C-shaped cross section, which has two endpoints and forms the guidewire track. The dimensions of the wall thicknesses between the inflation lumen and the guidewire track may be varied to help maintain the guidewire track and the gap between the endpoints of the C-shaped cross section such that a guidewire is maintained on the guidewire track and does not traverse the gap. In addition, a reinforcement may be included in the single lumen shaft to maintain the integrity of the guidewire track.