Primary myxoid liposarcoma of the thyroid gland is extremely rare. This report describes such a case. A 59-year-old woman was admitted for evaluation of a 6 x 6 x 5 cm nodule in the left lobe of the thyroid gland. Left thyroid lobectomy was performed without any postoperative treatment except for follow-up. Osseous and pulmonary metastasis developed 1 year later and the patient died 15 months after the surgery. The clinical course and treatment choice are discussed.