Congenital pericardial agenesis is an infrequent but usually asymptomatic condition, and is diagnosed as an incidental radiological finding. However, the association with cardiac malformations and myocardial herniation with the subsequent risk of sudden death has been reported. Chest plain films are a fundamental tool to raise the diagnostic suspicion. We present a clinical case of an 11-year-old patient who consulted for chest pain and dyspnea, in which, with the typical findings on chest radiography, pericardial agenesis was suspected and later confirmed by CT and MRI.