Diaphragmatic eventration (DE) describes an abnormal elevation of the diaphragm and may be congenital or acquired. Congenital DE is rare and seen more commonly in males. In pediatric patients, acquired DE is typically secondary to iatrogenic phrenic nerve injury or birth trauma. The left hemi-diaphragm is more commonly affected than the right. The spectrum of symptomatology can range from completely asymptomatic DE, detected incidentally on a chest radiograph performed for other reasons, to severe respiratory distress with inability to wean from mechanical respiratory support. We discuss the commonly performed investigations to confirm the diagnosis of DE, which can be challenging as the diaphragm is not always an easily studied structure. In severely symptomatic patients, the decision for operative intervention is an easier one. However, the decision to intervene in less severely affected patients can be difficult for the pediatric surgeon, and we present evidence that might guide that decision-making process in this chapter. We also discuss the outcomes of operative and observant management, as well as complications seen with both these management paths.