OBJECTIVE Extracardiac conduits are widely used to complete a Fontan circulation in patients with univentricular hearts. Although polytetrafluoroethylene conduits have proven good long-term patency, Dacron (polyethylene terephthalate) prostheses are still infrequently applied, with, as yet, no information on the long-term patency. METHODS All patients who received an extracardiac Dacron conduit (n = 12) were retrospectively studied. The initial conduit size was 16 mm in all recipients. The mean age at Fontan completion was 3.1 ± 0.7 years. Patients with clinical symptoms and/or significant conduit stenosis (>50% of diameter) underwent reoperation. RESULTS Of the 12 patients, 8 underwent reoperation (75%) at a mean interval of 6.5 ± 1.8 years after the Fontan operation. All conduits were replaced by an 18-mm polytetrafluoroethylene graft. The explants showed ubiquitous tissue deposits on the inner surface, with a residual internal diameter from 8 to 11 mm. All patients survived the extracardiac conduit replacement. Recovery was uneventful, except that 1 patient experienced long-lasting pleural fluid drainage. The mean hospital stay was 10.6 ± 12.0 days. CONCLUSIONS The incidence of extracardiac Dacron conduit stenosis in total cavopulmonary connection patients is high. These data indicate that the use of this type of conduit should be avoided. Vigilant follow-up is advised for those patients who have undergone Fontan completion with a Dacron extracardiac conduit.