Among 326 severely symptomatic neonates with coarctation with or without ventricular septal defect, four died before an initial procedure was performed. Among the 322 undergoing an initial procedure, survival for at least 24 months was 84%; the hazard function for death was lower initially but more prolonged in patients without than in those with ventricular septal defect. Important mitral valve anomalies coexisted in 5% of patients, left ventricular hypoplasia in 5% (more commonly in patients without ventricular septal defect), narrowing of the left ventricular outflow tract in 9% (more common in patients without ventricular septal defect), and narrowing of the proximal arch in 1%; one or more of these anomalies was present in most patients without ventricular septal defect who died. Five percent of the 322 patients had more than one of these coexisting anomalies, and 8% had just one. The most commonly used technique of repair of the coarctation was resection and end-to-end anastomosis, but no technique was a risk factor for death by multivariable analysis. Extension of the area of resection so that the end-to-end anastomosis was proximal to the left subclavian artery but distal to the left common carotid artery did not increase risk; extensions beyond this, and in the case of patch graft repair, extensions proximal to the left subclavian artery, did increase risk. Patch graft repair was associated with the highest prevalence (21%) of reintervention to the coarctation repair. Among patients with coexisting moderate-sized or large ventricular septal defects, repair of the coarctation, pulmonary trunk banding, and subsequent repair of the defect were associated with the highest 2-year survival, 97% in those with single ventricular septal defect. The risk-adjusted outcomes in two institutions were less good than in all others.