Ultrasonographic evaluation of the fetal heart for structural and functional abnormalities is vital for prenatal diagnosis and perinatal management. Even more important than up-to-date diagnostic equipment is keen observation and an understanding of fetal cardiac abnormalities. One diagnostic approach begins with the four-chamber view with particular attention to the normal symmetric sizes of all four cardiac chambers. Ventricular disproportion, inequality in ventricular size, is often an easily detectable sign of a cardiovascular abnormality. Segmental diagnosis of cardiac and visceral situs, ventricular outflow tracts for conotruncal abnormalities and the aortic and ductal arches is also vital for diagnosing affected fetuses.