Cardiac angiosarcoma is the most common among primary malignant cardiac tumors in adults. Malignant cardiac tumors commonly arise in the right-sided cardiac chambers unlike benign tumors that commonly arise in the left-sided chambers. Cardiac tumors on the left side need to be carefully assessed for malignant features for deciding treatment strategy and prognostication. We present the case of a 62-year-old female with a large left atrial mass infiltrating the interatrial septum and adjacent myocardial wall. Histology was suggestive of angiosarcoma. Although a radical excision was done, the tumor recurred within 6 months of the postoperative period and she died shortly after the recurrence.