Morgagni hernia is an extremely rare form of congenital diaphragmatic hernia. Only 6 cases of this condition have been reported in the English literature, as diagnosed prenatally. The prognosis of the disease is determined by the severity of the pulmonary hypoplasia and associated anomalies. Here we report a case of Morgagni hernia with massive pericardial effusion diagnosed by ultrasonography and MRI during the second trimester, enabling planning of appropriate treatment in the pre- and perinatal periods. Copyright (C) 2010 S. Karger AG, Basel