Among 183 neonates with interrupted aortic arch and ventricular septal defect entering a multiinstitutional study between 1987 and 1992, nine died before repair was accomplished. Among the remaining 174, survival at 1 month and 1, 3, and 4 years after repair was 73%, 65%, 63%, and 63%, respectively. The risk factors for death were low birth weight, younger age at repair, interrupted arch type B, outlet and trabecular ventricular septal defects, smaller size of the ventricular septal defect, and subaortic narrowing. Echocardiographically measured dimensions (expressed as Z-values) at all levels of the left heart-aorta complex were small. Two among thirty institutions were risk factors, and two others possibly were. Procedural risk factors for death after repair were (1) repair without concomitant procedures in patients with other important levels of obstruction in the left heart-aorta complex, (2) a Damus-Kaye-Stansel anastomosis, and (3) subaortic myotomy/myectomy in the face of subaortic narrowing. One-stage repair plus ascending aorta/arch augmentation had the highest predicted time-related survival in the 20% of patients with interrupted aortic arch and one or more coexisting levels of obstruction in the left heart-aorta complex, as did initial repair without or with aorta/arch augmentation in the 80% without these.