A bioplar sphinctertome for use in endoscopic retrograde sphincterotomy procedures includes an elongated, flexible, plastic tube having either a single or a double lumen and includes a segment near its distal end which is both flexible and conductive. This segment is connected by a wire extending through the lumen to a terminal at the proximal end of the device adapted to be coupled to an electrosurgical generator. A second, longitudinally movable wire passes through the lumen and is connected at the proximal end to a finger-operated slide mechanism while its distal end passes through a small aperture formed in the tube just proximal of the flexible conductive segment. That wire is then anchored distally of the flexible conductive segment so that when a tensioning force is applied to the wire, the distal end portion of the instrument will bow, with the exposed wire comprising the active electrode and the flexible conductive segment functioning as the return electrode. A two-piece handle assembly permits the sphinctertome to be treated as a disposable, single-use surgical instrument.