Congenital diaphragmatic hernias are usually found in neonates who present with respiratory distress. However, a significant number may remain clinically undiagnosed until much later in life. Of interest, the prognosis is felt to be better in this latter group. We describe three previously well patients (aged 2, 4, and 24 months) who suffered unexpected cardiorespiratory arrests due to unsuspected congenital diaphragmatic defects with intestinal herniation. Deaths resulted from cardiovascular and respiratory compromise due to visceral herniation that caused mediastinal and pulmonary compression.