Transoesophageal atrial pacing was used in 10 patients to interrupt post-operative atrial flutter after cardio-thoracic surgery. The method was successful in all cases. The arrhythmia was converted directly into sinus rhythm in 8 patients and into atrial fibrillation followed by spontaneous reversion to sinus rhythm in 2 patients. The results differed according to the underlying disease. Return to sinus rhythm was the rule in all patients who underwent coronary artery bypass grafting and pneumonectomy, whereas transient atrial fibrillation seemed to be more frequent (and should be considered a satisfactory result) in patients with heart valve surgery. Relapses of arrhythmias seemed to be more resistant to transoesophageal stimulation irrespective of the operation performed. The method is non-invasive, easy to carry out and safe in patients receiving digitalis. The risk of ventricular pacing is very low. The burning sensation and chest pain experienced during stimulation are well tolerated. Transoesophageal pacing is as effective as epicardial atrial stimulation and more effective in such patients than temporary transvenous atrial pacing.