A case of intravenous leiomyomatosis of the uterus with extension into the heart discovered in a 34-year old patient who suffered from dyspnea is reported. The findings suggest that intravenous leiomyomatosis originates from the smooth muscle component of uterine veins. Only 30 cases of intravenous leiomyomatosis with intracardiac extension have been reported. Two-dimensional echocardiography showed an abnormal mass in the right atrium. Pelvic echography showed an abnormal mass in the pelvis. In case of cardiac involvement, spontaneous prognosis remains poor. The primary goal of surgery is the complete removal of the tumor. Hormonotherapy should also be considered in case of unresectable residual tumor. A long-term follow-up of patients after resection of intravenous leiomyomatosis is needed because recurrences up to 17 years after primary resection have been reported.