Cardiac hernias are rare occurrences resulting from congenital pericardial defects, trauma, or postsurgical changes. Difficult to diagnose, they can lead to significant morbidity and mortality. The first reported case of left ventricular herniation in a pediatric cardiac transplant recipient is presented, and the literature concerning diagnosis and management is reviewed. Clinicians must have a high index of suspicion to diagnose this rare and potentially lethal defect.