Abstract: Objective To observe the tolerance and safety of enteral nutrition (EN) and parenteral nutrition (PN) in neonates with critical illness supported with extracorporeal membrane oxygenation (ECMO). Methods Neonates admitted to Pediatric Intensive Care Unit (PICU) in Children's Hospital of Fudan University and receiving venoarterial extracorporeal membrane oxygenation (VA-ECMO) combined with EN and PN were retrospectively collected from August 10, 2015 to March 31, 2020. The newborns with complex and refractory congenital heart disease were excluded. Demographic data (gestational age, birth weight, sex, etc. ), nutrition-related laboratory data (biochemical and electrolytes tests), the initial time and daily doses of PN and EN, the vasoactive agents at the beginning of EN, the ventilation time，the morbidity and the prognosis were reviewed for each patient during hospitalization. Results A total of 11 neonates underwent ECMO. All of them were supported with PN, and 9 of them received EN. There was no necrotizing enterocolitis (NEC). Among 8 survivors, 7 patients' weight was >P10 at discharge according to the standard of World Health Organization. During the period of ECMO, all patients had experienced thrombocytopenia and hypophosphatemia, and cholestasis, hypocalcemia and hypomagnesemia were found in 6, 10 and 5 cases respectively. There was a statistically significant difference in serum concentration of direct bilirubin between ECMO with CRRT group and ECMO without CRRT group ［70.0(32.4,182.4) μmol·L-1 vs 13.7(11.2, 15.7) μmol·L-1，P =0.015］. Conclusion It is safe and feasible to treat critically ill neonates supported by ECMO with enteral and parenteral nutrition, but it is necessary to closely observe clinical situations and monitor laboratory indexes.