Objective: To identify prenatally diagnosed cases of hypoplastic left heart syndrome (HLHS) and then to determine postnatal outcomes after surgical interventions. Methods: An ultrasound and pediatric cardiology database was used to identify all fetuses diagnosed prenatally from 1991-1996 with HLHS. Fetal karyotypes were performed on cultured amniocytes. After diagnosis, parents were given several management options: pregnancy termination before 22 weeks, postnatal hospice care, or surgery using the Norwood procedure or cardiac transplantation. Ultrasound and echocardiography findings were later compared to karyotype results and postnatal outcome data. Results: Fifteen fetuses with HLHS were identified. Two (16%) chromosome abnormalities and three (20%) structural defects were detected. Three mothers (20%) opted for pregnancy termination, two (13%) chose postnatal hospice care, and one aneuploid fetus had an intrauterine death. Nine parents (60%) chose surgery for their infants; however, one infant was not an appropriate surgical candidate due to a coexisting diaphragmatic hernia. Eight infants underwent surgery and two survived (25%). Of the four infants scheduled to undergo the Norwood procedure, one died preoperatively, two died intraoperatively, and one infant survived and is doing well at age 8 months. Of the four infants scheduled for cardiac transplantation, two died awaiting transplant and one died postoperatively. One infant survived cardiac transplantation but has microcephaly and developmental delay at age two. Conclusions: In prenatally diagnosed HLHS at our institution, the survival rate following surgery for infants felt to be the best candidates was only 25%. © 1999 Wiley-Liss, Inc.