Primary synovial sarcoma of the neck is an extremely rare malignant neoplasm. The occurrence of synovial sarcoma in the soft tissue of the neck was first reported in 1954 and thereafter about 50 cases were reported in worldwide. No case was reported in Korea. A case of cervial sarcoma was experienced in the Department of Sung Sim Hospital. It was found in the anterior neck of a 30-years-old male. The patientnoticed a thumb-tip sized mass in the anterior neck and the mass grown up rapidly up to adult's fist size with 4 months duration. Fistulogam of the neck mass revealed a multilocular cystic appearance, which is diagnostic findings of cystic hygroma. On operation there was a lobulated grayish white to partly pinkish adult-fist sized mass, with large area of cystic degeneration, which was filled with reddish brown necrotic material. The mass was partly adhered to the hyoid bone. Radical excision could not be performed due to massive bleeding. Several fragments of biopsy materials were sent to the department of Clinical Pathology and were measured 3×2×0.6 cm in aggregates. Grossspecimen shows grayish white discoloration, and inner surface was coated by focal areas of reddish brown necrotic materials. Microscopically, biopsy materials represented the characteristic biphasic cellular pattern of a synovial sarcoma, with epithelioid and fibrosarcoma-like areas in varying propotions.