Malignant oncocytomas are extremely rare tumours of the salivary glands. Fewer than 50 cases have been reported in the world literature so far, 34 of which were located in the parotid gland. Only three of these tumours have been located in the submandibular gland. We report one further case of a malignant oncocytoma of the submandibular gland in a 47-year-old man. Since a definite histological diagnosis of malignant oncocytoma can rarely be made both clinical and histopathological findings are essential in establishing the diagnosis. Treatment consists of wide surgical excision, neck dissection and post-operative radiotherapy. The prognosis with regard to five-year survival is poor becauseof metastatic disease.