Primary soft tissue sarcoma of the heart is encountered infrequently in clinical practice. Treatment is reported of an intracardiac malignant fibrous histiocytoma, consisting of maximal surgical resection followed by 5600 cGy of conventionally fractionated radiation therapy. Transesophageal echocardiograms done during follow-up were useful in assessing tumor control. Aspects of patient care are discussed in conjunction with a review of the available literature.