Introduction: Systemic-pulmonary artery shunts (BTS) provide a stable source of pulmonary blood flow (PBF) in infants with some forms of single ventricle congenital heart disease (SVCD). These infants are at risk for necrotizing enterocolitis (NEC), thought to be due to diastolic run-off in the BTS, resulting in decreased intestinal perfusion. We sought to describe the prevalence and outcomes of NEC and identify risk factors in infants with BTS-dependent SVCD.Methods: We conducted a retrospective cohort study of infants with BTS (with or without concomitant Norwood) and SVCD between 2010 and 2015 at our institution. We excluded those with a source of PBF other than the BTS, right ventricle to pulmonary artery shunts, and ductal stents. NEC was defined as clinical concern for reduction in intestinal blood supply, requiring management with antibiotic therapy and/or exploratory laparotomy. Demographic, clinical, surgical, and hospitalization characteristics were collected to describe outcomes and identify risk factors.Results: Of 178 included patients, NEC occurred in 18 (10%) at a median of 13 (range 1-65) days after BTS placement. Hematochezia was the most common presenting sign and management included antibiotics in all and surgical exploration in 2 (11%). Patients with NEC had lower weight-for-age z-scores at BTS surgery (-1.1 ± 1.5 v. -0.4 ± 1.2, p=0.022), were more likely to be mechanically ventilated one week after BTS surgery (33% v. 13%, p=0.033), and were more likely to have post-operative ventricular dysfunction by echo (33% v. 7%, p=0.001). There was a trend toward increasing need for transcatheter BTS intervention among NEC patients (35% v. 17%, p=0.056). There were no significant differences in other demographic, clinical, or surgical characteristics. NEC patients had worse outcomes including longer median post-operative lengths of stay (42 v. 17 days, p<0.001) and more frequent need for ECMO (28% vs. 10%, p=0.027). Mortality was higher, although not statistically different (33% v. 18%, p=0.1).Conclusions: In this single center study, NEC occurred in 10% of infants with SVCD and BTS-dependent PBF and was associated with worse outcomes. Clinicians should be vigilant in monitoring for NEC in patients with risk factors identified in this study.