We report the case of an intrapericardial teratoma, a rare tumour in infants, prenatally diagnosed and successfully treated thanks to a multidisciplinary approach. An intrapericardial cystic mass (2.5 cm) with pericardial effusion was identified in a foetus at 32 weeks gestational age (GA). Intrauterine pericardiocentesis was performed immediately (40 ml) and repeated at 33 weeks (25 ml) and then at 34 weeks GA, just before birth (36 ml). Considering the rapid growth of the mass and the risk of hydrops, vaginal delivery was induced. A baby girl weighing 1.98 kg was born without cardiorespiratory compromise. Echocardiography and thoracic CT-scan located the 4.0×3.0 cm cystic mass between the left atrial appendage and the left superior pulmonary vein. At three days of life, the mass was completely removed without cardiobypass. It arose from the ascending aorta. Postoperative course was uneventful. Pathology diagnosed an immature intrapericardial teratoma. As long-term follow-up is required, alpha-fetoprotein can be a valid tool to monitor a possible recurrence. A multidisciplinary approach allows successful prenatal management and postnatal tumour surgery.