BACKGROUND: Factors that determine the need for Gastrostomy tube (G-tube) placement in infants with complex congenital heart defects (CHD) are variable. We aim to identify factors that improve counseling of expectant parents regarding postnatal outcomes and management. METHODS: We performed a retrospective review of medical record of infants with prenatal diagnoses of complex CHD between 2015-2019 in a single tertiary care center and assessed risk factors for G-tube placement with linear regression. RESULTS: Of the 105 eligible infants with complex CHD, 44 infants required G-tube (42%). No significant association was observed between G-tube placement and chromosomal abnormalities, cardiopulmonary bypass time or type of CHD. Median days on noninvasive ventilation (4 [IQR 2-12] vs. 3 [IQR 1-8], p = 0.035), time at which gavage-tube feeds were started postoperatively (3 [IQR 2-8] vs. 2 [IQR 0-4], p = 0.0013), time to reach full-volume gavage-tube feeds (6 [IQR 3-14] vs. 5 [IQR 0-8], p = 0.038) and intensive care unit (ICU) length of stay (LOS) (41 [IQR: 21 – 90] vs. 18 [IQR: 7 – 23], p < 0.01) were associated with G-tube placement. Infants with ICU LOS duration longer than median had almost 7 times the odds of requiring a G-tube (OR: 7.23, 95% CI: 2.71-19.32; by regression). CONCLUSIONS: Delay in initiation and in reaching full-volume gavage-tube feeds after cardiac surgery, increased number of days spent on non-invasive ventilation and in the ICU were found to be significant predictors for G-tube placement. The type of CHD and the need for cardiac surgery were not significant predictors for G-tube placement.