Intravenous leiomyomatosis with cardiac extension is rare and may result in a fatal outcome. A 58-year-old woman with a surgical history of myoma uteri was admitted to our hospital for treatment of intravenous leiomyomatosis extending into the right atrium through the inferior vena cava. We partially resected the tumor inside the right atrium and the inferior vena cava via the right atrium using cardiopulmonary bypass. There is no progression of the residual tumor after 25 months of follow-up.