The records of 14 patients with fibrosarcoma of the jaws--10 in the mandible and four in the maxilla--from the files of the Netherlands Committee on Bone Tumours were studied. The mean age of the patients was 30 years; more men than women were involved; pain and especially swelling were the symptoms most frequently present. The radiographic appearance often indicated the malignant nature of the lesion. Histologically 42% of the tumours were low-grade malignant. The 5-year survival rate was 71%, which is more favourable than either fibrosarcoma located elsewhere in the skeleton or osteosarcoma of the jaws. Radical surgery is the therapy of choice. All cases with an unfavourable course acquired lung metastases.