In a 61-year-old patient with unstable angina an attempt was made to dilate a severe stenosis in a tortuous obtuse marginal branch. The initial attempt with conventional equipment was not successful; although the wire could be advanced distal to the stenosis, a 2.0 balloon did not cross the stenosis. A second attempt with a balloon on a wire device resulted in fracture of this catheter, with the distal 2.8-cm-long fragment looped in the left coronary artery. Immediate bypass surgery was performed and the broken fragment was easily removed from the left coronary ostium. The patient made an uneventful recovery.