Cardiac rhabdomyomas are benign tumours closely associated with tuberous sclerosis. We report on a neonate with a cardiac rhabdomyoma, which simulated tricuspid atresia with duct-depending pulmonary perfusion due to almost complete obliteration of right ventricular cavum. Under infusion of prostaglandin E1 the newborn stabilized and was successfully operated on the 3rd day of life. We conclude that successful tumour resection is possible in neonates with cardiac rhabdomyomas causing relevant hemodynamic obstruction.