Pentalogy of Cantrell is a rarely seen syndrome that, in full form, includes a midline supraumbilical abdominal defect, defect of the lower sternum, deficiency of the diaphragmatic pericardium, deficiency of the anterior diaphragm, and congenital cardiac anomalies. Cases not fulfilling these criteria but including various combinations of them, provided that they include at least either a sternal defect or intracardiac and ventral abdominal wall abnormalities, are regarded as variants of the classic form. A case of a variant of Cantrell's pentalogy detected by sonography at 21 weeks' gestation is presented. Clinical examination of the aborted fetus confirmed the sonographic findings. Because of the poor prognosis of the condition, early antenatal sonographic diagnosis is important because it may allow for elective abortion before viability.