Desmoid tumor is derived from musculoaponeurotic origin. Histo-logically it consists of interwining bundles of spindle cells in a collagen matrix, with normal mitosis and does not metastasize. Clinically, however, it is infiltrative and tends to recur locally. A case of demoid tumor in the neck of an eight-year-old boy was reported. He was presented with the chief complaint of a painless, firm swelling over the left mandibular angle regior for one month. The mass was found attach to the inferior border of the left mandibular angle. CT scan showed a well-defined homogenous mass with calcified spur near the mandibular angle. Microscopic findings from incisional biopsy were poor-defined tumor margin and bundles of spindle cells in a collagen matrix. The pathologic report was desmoid tumor. Under general anesthesia, the tumor was completely excised and the bone surface was trimmed and smoothened. After a follow-up period of nine months, no recurrence was noted.