The authors report their experience of 28 cases of the Wolff-Parkinson-White (WPW) syndrome treated by surgery. Four patients had multiple accessory pathways; of the 32 bundles of Kent detected, 16 were in the postero-septal region. Surgery, performed under cardio-pulmonary bypass after epicardial mapping, consisted in atrioventricular disconnection using no special physical agent. With the exception of 2 cases, the left lateral accessory pathways were operated on using a classical left endoatrial approach whereas in the right lateral and septal forms the main procedure of dissection of the right atrioventricular groove was carried out by an epicardial approach. There was one operative death due to haemodynamic and haemorrhagic problems in a top class athlete with two bundles of Kent, the interruption of which required two consecutive bypass procedures. In the 27 survivors, 29 of the 30 accessory pathways were successfully interrupted (96%). The only failure occurred in a patient with two bundles of Kent. On the other hand, in 2 patients, complete atrioventricular block was successfully obtained by surgical section of the His bundle during the same procedure in one case, and by postoperative catheter ablation in the other case in which surgery had failed. There were no cases of accidental permanent atrioventricular block. The results in this series confirm the value of surgery in the treatment of the WPW syndrome, especially in the septal forms which are reputed to be the most difficult but in which the approach is greatly simplified by the initial dissection of the tricuspid ring by an epicardial approach. If these results lead to an increase in the surgical indications in this condition, it must be emphasised that one of the principal remaining problems is that of multiple accessory pathways which may be difficult to detect even at surgery.