Operative survival after the Norwood procedure has significantly improved during the past 10 years. However, there remains attrition among Norwood survivors before reaching planned second-stage palliation. The purpose of this study was to evaluate potential risk factors for interstage mortality among Norwood survivors. All patients undergoing the Norwood procedure at the Medical University of South Carolina from January 1996 through January 2001 were retrospectively reviewed. Patient and procedural variables were examined as potential risk factors for interstage mortality. Among 50 Norwood survivors, 8 (16%) died prior to second-stage palliation. The mean age at death was 102 +/- 72 days (median, 61; range, 35-208). By multivariate analysis, the presence of an arrhythmia in the postoperative period (p = 0.02) and decreased ventricular function at hospital discharge (p = 0.05) were identified as risk factors for interstage mortality. There remains a significant risk for interstage mortality among Norwood survivors. Patients with postoperative arrhythmias and/or decreased ventricular function at discharge are at increased risk for interstage death after Norwood procedure. More frequent follow-up and aggressive medical management of arrhythmia or decreased function may be warranted for these high-risk patients.