Sudden death resulting from intracardiac leiomyomatosis is rare. In this case, a 50-year-old woman was found to have intracardiac leiomyomatosis, which originated in veins in the broad ligament. Tumor filled the entire inferior vena cava and extended into the right heart where it had embolized and occluded the right main pulmonary artery. The mechanism of death was sudden right heart failure.