A markedly enlarged right heat with a normal outflow tract was detected by fetal echocardiography in a fetus at 28 week's gestation. Follow-up scan at 32 week's gestation also showed asymmetric ventricles. The neonate were normal after delivery. Marked discrepancy between the sizes of the right and left ventricle generally indicates structural heart anomaly, such as coactation of aorta, hypoplastic left heat syndrome, or right ventricular outflow tract obstruction. But we experienced a case of marked fetal ventricular size discrepancy on 4 chamber view and turned out to be normal heart postnatally.