<b><i>Objectives: </i></b>To compare outcomes in pregnancies with a prenatal detection of congenital diaphragmatic hernia (CDH) with children diagnosed after birth, treated at the same institution, and to determine the ability to predict prognosis through measurements of the observed to expected lung-to-head ratio (O/E LHR). <b><i>Methods:</i></b> This is a retrospective review of all children with CDH treated at our institution during 2006-2014. We compared outcomes of infants referred for surgery after postnatal diagnosis with outcomes of infants with prenatally diagnosed CDH. <b><i>Results:</i></b> In the prenatal group, O/E LHR was significantly different between survivors and deceased patients, with a cutoff at 35% O/E LHR. Survival to discharge and 1-year survival were significantly higher in the postnatal group that required intubation within 24 h; i.e., 92 and 89% versus 85 and 73% in the prenatal group (p < 0.05). There was less need for extracorporeal membrane oxygenation (ECMO), 41 versus 60%, and patch, 41 versus 75% (p < 0.001), in the postnatal group with early diagnosis compared with the prenatal group, respectively. <b><i>Conclusion: </i></b>Children with prenatally diagnosed CDH represent a population with a more severe condition compared to infants diagnosed after birth. They have poorer outcomes with higher needs for ECMO or use of patch, and lower survival rates were observed at an O/E LHR below 35%.