Primary cardiac neoplasms are an infrequent disease, as most of the tumors arising in the heart are metastatic. Between the malignant tumors, sarcomas are the most frequent ones, accounting for at least 95% of them. We report the case of a 70-year old woman, diagnosed of primary cardiac osteosarcoma arising in the left atrium. Although complete excision of the tumor was performed, the disease relapsed and subsequently developed metastatic disease. In this paper, we also review briefly the management of this rare disease and the therapeutic options.