A single operator exchange biliary catheter having a tubular member extending proximally from the proximal guidewire port. The tubular member defines a guidewire lumen extension adapted to permit the guidewire to be retracted from guidewire lumen and re-inserted therein. By retracting the guidewire from the guidewire lumen and into the guidewire lumen extension, fluid may be readily injected via the guidewire lumen without encountering resistance to fluid flow from the guidewire. The guidewire lumen extension also maintains guidewire lumen access such that the guidewire may be easily re-inserted into the guidewire lumen.
