A 17-year-old girl presented with an enlarged cardiac silhouette on routine chest roentgenogram. After clinical evaluation, echocardiography, and pericardiocentesis failed to provide a diagnosis, exploratory thoracotomy and biopsy revealed an unresectable left ventricular fibroma. The tumor continued to enlarge and began causing ventricular arrhythmia. Therefore, she underwent cardiac transplantation 2 years after the initial diagnosis was made. She is now alive nd well 18 months following transplantation.