Between January 1990 and February 1993, 73 patients underwent first-stage reconstruction for hypoplastic left heart syndrome at the University of Michigan Medical Center. During this period, surgical reconstruction remained essentially constant and consisted of a pulmonary artery-to-aorta anastomosis with allograft augmentation of the ascending, transverse, and proximal descending aorta, restriction of pulmonary blood flow with a polytetrafluoroethylene shunt from the innominate artery to the central pulmonary artery confluence, and atrial septectomy. Hospital survival was 62 of 73 patients, 85% (70% confidence limits: 80% to 89%). These results stand in marked contrast to those obtained during the earlier years of our experience from 1986 to 1989 when only 21 of 50 patients (42%, 70% confidence limits: 35% to 49%) survived (p = 0.001). Among the most recent group of patients, only 2 of 7 patients older than 1 month of age at operation survived, whereas 60 of 66 (91%, 70% confidence limits: 87% to 94%) patients younger than 1 month of age survived (p = 0.0001). Anatomic subtype and ascending aortic diameter were not predictive of survival. Actuarial survivals for those patients younger than 1 month of age at the first-stage operation, including hospital deaths and subsequent operative procedures, were 81%, 74%, and 74% at 6 months, 1 year, and 2 years, respectively. These results indicate that survival for patients after first-stage reconstruction for hypoplastic left heart syndrome has significantly improved in recent years. Older age was a strong risk factor, with a hospital survival of 91% for those patients undergoing first-stage palliation within the first month of life. These data have important implications for the type of operative intervention and its timing.