A technique for extracardiac conduit fenestration specifically devised to achieve long-term patency is presented. From 2001 to 2007, 65 patients underwent a fenestrated extracardiac Fontan procedure using this technique where the atrial orifice of the divided inferior vena cava was sutured in an end to side fashion to the leftward aspect of the conduit. The circumferential suture line was centred by the fenestration but remained away from the edge of the latter. All patients receive oral anticoagulation. Clinical and echocardiographic follow-up were obtained. Concurrent follow-up was 100%. There was one early death (mortality 1.5%). Two patients had Fontan failure requiring takedown and another two were transplanted. The fenestration was found to be patent in the rest of patients of the series (n=60) at a median follow-up of 11 months (range 1-91). The mean velocity across the fenestration was 1.6+/-0.55 m/s. No patient required reintervention related to the fenestration. All patients remained in sinus rhythm. This technique is easily reproducible, consistently provides long-term patency and low incidence of complications. The use of inferior vena cava orifice of the right atrium explains the absence of supra ventricular arrhythmias.