We sought to determine the prevalence of outcomes and associated patient and management factors for neonates with interrupted aortic arch. From 1987 to 1997, a total of 472 neonates were enrolled prospectively from 33 institutions. Competing risks methodology was used to determine simultaneous risk and associated incremental risk factors for death, initial and subsequent left ventricular outflow tract procedures, and arch reinterventions. Overall survival was 59%at 16 years after study entry but improved with successive birth cohort. In general, risk factors for death in each of the competing risks analyses included lower birth weight, younger age at study entry, type B interrupted aortic arch, and major associated cardiac anomalies. Of 453 patients who had interrupted aortic arch repair, after 16 years 33%had died and 28%had undergone an arch reintervention. Reintervention was more likely for those who had truncus arteriosus repair, interrupted aortic arch repair by a method other than direct anastomosis with patch augmentation, and the use of polytetrafluoroethylene as either an interposition graft or a patch. From study entry, competing risks after 16 years showed that 28%had died and 34%had undergone an initial left ventricular outflow tract procedure. Initial left ventricular outflow tract procedure was more likely for those with single ventricle, type B interrupted aortic arch, bicuspid aortic valve, or anomalous right subclavian artery. Among those who had undergone an initial left ventricular out-flow tract procedure, after 16 years 37%had died and 28%had undergone a second procedure. Anatomic features affect mortality and initial left ventricular outflow tract procedures, whereas characteristics of the arch repair affect arch reintervention. We sought to determine the prevalence of outcomes and associated patient and management factors for neonates with interrupted aortic arch. From 1987 to 1997, a total of 472 neonates were enrolled prospectively from 33 institutions. Competing risks was used to determine simultaneous risk and associated incremental risk factors for death, initial and subsequent left ventricular outflow tract procedures, and arch reinterventions. Overall survival was 59% at 16 years after study entry but improved with successive birth cohort. In general, risk factors for death in each of the competing risks analyzes included lower birth weight, younger age at study entry, type B interrupted aortic arch, and major associated cardiac anomalies. Of 453 patients who had interrupted aortic arch repair, after 16 years 33% had died and 28% had undergone an arch reintervention. was more likely for those who had truncus arteriosus repair, interrupted aortic arch repair by a method other tha n direct anastomosis with patch augmentation, and the use of polytetrafluoroethylene as either an interposition graft or a patch. From study entry, competing risks after 16 years showed that 28% had died and 34% had undergone an initial left ventricular outflow tract procedure. left ventricular outflow tract procedure was more likely for those with single ventricle, type B interrupted aortic arch, bicuspid aortic valve, or anomalous right subclavian artery. Among those who had undergone an initial left ventricular out-flow tract procedure, after 16 years 37% had died and 28% had undergone a second procedure. Anatomic features affect mortality and initial left ventricular outflow tract procedures, while characteristics of the arch repair affect arch reintervention.