A review of the Japanese literature revealed 41 well-documented metastatic tumours of the mouth and jaws. The incidence was 1.5 times higher in females than in males and 76% were in the fourth to seventh decades with a mean of 44 years. Instead of the breast which is the most frequently encountered site of origin of metastatic tumours in Caucasians, the uterus followed by the lung, kidney and stomach was the site of primary carcinoma with the highest incidence. Histologically, carcinomas of glandular origin showed the highest rate of metastasis which was followed by choriocarcinomas. Squamous cell carcinoma and sarcoma were unusual. Metastasis occurred in the gingiva in 23 cases and bony involvement was noted in 16 cases. The most common symptoms were swelling, pain, bleeding, paraesthesia and loosening of teeth. The radiographic appearance was quite variable with no specific diagnostic characteristics. The oral lesions were treated by surgery, irradiation or chemotherapy in 32 cases, while no treatment was carried out in seven cases. Prognosis was very poor with 33 fatal cases due to multiple metastases.