We report the use of video-assisted cardioscopy (VAC) to assess the complete resection of a giant sessile rhabdomyoma of the left ventricle (LV) in a case of suspected neonatal tuberous sclerosis. A fetal echocardiogram performed at 20 weeks of gestation identified the mass at the apex of the LV and attached to the interventricular septum (IVS). Further echocardiography during the pregnancy demonstrated moderate growth of the LV mass. This was occupying more than two-thirds of the LV cavity after the delivery, and there were concerns of LV outflow tract obstruction. The 4-kg newborn underwent LV tumor excision via a left atrial approach at the age of 12 days. The mitral valve (MV) apparatus and the IVS had strong attachments to the mass. The tumor was successfully resected. In view of the invasiveness of the tumor, a decision was taken to perform an intracardiac assessment using a VAC to detect any iatrogenic complication. A Karl Storz Neuro Endoscope probe 4 mm in diameter and 14 mm in length with an angulation of 0° was passed into the left ventricular cavity through the MV with the aim to detect residual tumor and to identify any iatrogenic complications due to the extensive resection. Video-assisted cardioscopy allows visualization of inaccessible intraventricular structures avoiding ventriculotomy, which can cause ventricular dysfunction, arrhythmias, and aneurysm formation. The VAC was shown to be very useful in this situation, and the process can easily be repeated as required.