The first case of non-operative occlusion of a large coronary to bronchial anastomosis is described. The patient who had severe angina had also a critical stenosis of the anterior descending coronary artery which was successfully dilated by an angioplasty procedure. An occluding balloon was detached in the large distal circumflex coronary artery, beyond all the normal branches. At a repeat catheterisation study seven months later the balloon was intact and in position, and the anastomosis remained occluded.