Intravenous leiomyomatosis is a rare smooth muscle tumor. We report two cases of intravenous leiomyomatosis that grew along different routes of the venous system into the inferior vena cava and the right atrium. The different route of extension makes a difference in the ease of excision of tumor masses. Using MEDLINE together with the references in each publication, we identified all cases of intracardiac leiomyomatosis reported in the English literature in the period between 1980 and 2003 and performed a brief review on this potentially lethal disease entity.