A 70-year-old man with a history of lacunar stroke about a year before was incidentally found to have primary cardiac tumor during the work up for orthopedic surgery. It uniquely originated from the coumadin ridge between the left upper pulmonary vein and the left atrial appendage. He underwent tumor resection under cardiopulmonary bypass with superior transseptal approach. It allowed enough surgical exposure for en-bloc resection of the tumor with minimal risk of tumor embolisms. The pathological report confirmed that the tumor was a cardiac myxoma. The postoperative course was uneventful with no stroke nor embolism complications. We experienced a rare myxoma orginating from the coumadin ridge and successfully resected it with superior septal approach.