During the fetal-neonatal period, a primary cardiac tumor may be completely asymptomatic and such tumors may be incidentally discovered by echocardiography. A four-hour-old male was diagnosed to have a cardiac tumor by post-natal echocardiography and was observed closely. Surgery was indicated immediately at the 3 week follow-up examination when the tumor was found to have obstructed the right ventricle outflow. The tumor was resected successfully and its histopathology indicated that it was a fibroma. Follow-up echocardiograms and magnetic resonance imaging 5 months postoperatively demonstrated no evidence of any remaining tumor and his RV function was good.