Congenital diaphragmatic hernia (CDH) is a rare congenital defect. Most cases are currently diagnosed either prenatally by ultrasound or shortly after birth. Late presentation of CDH is uncommon, and symptoms vary greatly. Here we describe two cases. The first concerns a 9-year-old boy with abdominal pain. The symptoms were interpreted as constipation and he was admitted for a high enema. After a few hours he developed severe respiratory distress; chest X-ray revealed a tension gastrothorax, and thoracostomy resulted in immediate respiratory improvement. In the second case, a 6-month-old girl presented with haematemesis and electrolyte imbalance. She was admitted for rehydration and correction of the electrolyte balance. A chest X-ray was performed because of persistent vomiting, and this showed an intrathoracal stomach. Late presentation of CDH is often misdiagnosed, with the risk of serious morbidity and mortality. Tension gastrothorax is a rare, life-threatening complication which should be treated by emergency gastric decompression..