Between August 1991 and August 1993, 75 patients (42 male) with Wolff Parkinson White syndrome (43 concealed) were subjected to radiofrequency ablation of accessory pathways at our institution. 55 had left, 8 postero septal, 2 anteroseptal and 10 right accessory pathways. A retrograde aortic technique with placement of the ablation catheter in close proximity to the mitral annulus was used for most of the patients with left accessory pathways and for some with posteroseptal pathways. The right, anteroseptal and some posteroseptal pathways were ablated using a right heart approach placing the ablation catheter in the tricuspid annulus. Ablation was successful in 61 patients (81%). One subject developed a fatal cardiac tamponade after a transeptal catheterization and was unrelated to the ablation per se. It is concluded that radiofrequency ablation of accessory pathways is a curative procedure for a great majority of patients with Wolf Parkinson White syndrome.