The presence of pericardial effusion in neonates usually indicates a poor prognosis. Here, we report a case of isolation of cardiac tamponade in a newly born. This may be related to vertical human parvovirus B19, an infection with atypical clinical manifestation. Any neonate with unexplained fetal pericardial effusion should always be tested for parvovirus B19 infection, even in the absence of known and proved fetal exposure. Despite the etiology of a tamponade the only reasonable procedure is a surgical evacuation during diagnosis.