Intravenous leiomyomatosis is a rare entity of benign smooth muscle invading into the lumen of veins. We describe a case of intracardiac leiomyomatosis originating from the right gonadal vein, growing in the inferior vena cava, and extending into the right atrium. A 54 years old woman presented with chest discomfort and syncope four years after the removal of an uterine leiomyoma. The tumor was successfully removed in a two-staged operation using total circulatory arrest with a cardiopulmonary bypass, which proved to be a histologically benign leiomyoma. Although these tumors are histologically benign, they sometimes extend into the cardiac cavity and can cause sudden death due to their incarceration into the atrioventircular orifice. We report this rare case with a review of the literature.