Mandibulectomy or maxillectomy was performed in dogs for the removal of 100 bone-involved oral tumours of varying histological type. These techniques provided excellent results when used for the excision of carcinomas achieving one year survival rates for basal cell carcinomas (acanthomatous epulides) and squamous cell carcinomas of 100 and 84 per cent, respectively. Mandibulectomy and maxillectomy were, therefore, considered to achieve good wide local excision and to be the techniques of choice for the management of oral carcinomas. Prognoses for sarcomas were, however, considerably poorer. There was a high incidence of local recurrence (32 per cent) and distant metastasis (27 per cent) and one year survival rates for fibrosarcomas, osteosarcomas and malignant melanomas were 50, 42 and 0 per cent, respectively. Mandibulectomy and maxillectomy were not considered to achieve radical local excisional margins in all cases and were inadequate as the sole form of treatment for sarcomas of the oral cavity. Mandibulectomy and maxillectomy may be useful, however, as part of a combined modality approach to oral sarcomas or may be justified as the sole therapy where adjuvant modalities are not available.