Fibrous histiocytomas are soft tissue tumors of histiocytic origin. One percent prove to be malignant. Reliable histologic criteria of malignancy are few, if any, and the diagnosis of malignancy often must be made on clinical (metastases) rather than histologic grounds. Thirty-five cases originating in various deep structures of the head and neck, excluding the orbit, have been reported in the literature since 1972. One additional case, a malignant tumor of the submandibular gland, is added herewith. Recurrence following initial surgery has been common and stems from inadequate excision of the primary lesion. Microscopic spread of this tumor from its primary site calls for radical rather than conservative surgical excision. At present, radiotherapy and chemotherapy appear to be of little value in the treatment of these tumors.