A previously healthy gravida developed chest pain and progressive dyspnea several months after delivery. A right ventricular mass rising from the septum and floating through the pulmonary valve was detected, with multiple lung nodules. With the suspicion of a primary sarcoma of the heart, she was referred for cardiac surgery. Microscopic observation of the cardiac neoplasm revealed malignant trophoblast. There was no evidence of disease in the uterus and adnexa. Combination chemotherapy with EMA-CO schedule was instituted because of the high-risk score. A complete recovery was achieved after 20 weeks of treatment and the patient is free of disease 4 years after the end of chemotherapy and is now pregnant again.