AbstractBackgroundLung herniation is a rare complication of heart–lung transplantation that can be fatal owing to vascular compromise and airway obstruction. To date, only five cases of lung herniation related to heart–lung transplantation have been reported in the literature; however, to the best of our knowledge, this is the first worldwide report of heart–lung transplantation‐related lung herniation in an infant.MethodsWe describe the case of lung herniation as a rare heart–lung transplantation‐related complication in an infant. A 12‐month‐old female baby developed severe bronchopulmonary dysplasia with severe pulmonary hypertension, and she underwent extracorporeal membrane oxygenation for cardiac collapse and lung support. Then, we performed heart–lung transplantation to manage the irreversible deterioration of her lung function. After the heart‐lung transplantation, we found the radiological abnormalities persisted on follow‐up chest radiographs until the 13th postoperative day diagnosed as lung herniation of the right lower lobe on chest computed tomography.ResultsAfter the relocation of the herniated lung, the clinical condition of the patient improved, and the patient is currently growing without any respiratory symptoms.ConclusionsIn this case report, we emphasize that clinical awareness and high suspicion of this rare complication are needed for early diagnosis and proper treatment to prevent post‐transplantation morbidity and mortality related to potential ischemic injury.