Sialoblastoma is a rare tumor of salivary gland origin, developing in the fetal or neonatal period. Most tumors arise in parotid gland, and rarely in submandibular gland. Because of its rare incidence, diagnosis of the sialoblastoma in head and neck tumors of children is not easy. The case of a congenital submandibular gland sialoblastoma is presented. A neonate was transferred right after birth due to a submandibular mass. CT scan showed a lobulating mass located posterior to the left submandibular gland, suggesting neurogenic tumor or myofibroma. The tumor was excised easily after division of a duct-like structure connecting with the submandibular gland. The microscopic findings showed the basaloid cells and ductules forming cellular nests, separated by thin fibrous tissue. Immunohistochemical staining was positive for cytokeratin, vimentin and Ki-67, which was consistent with sialoblastoma.