Oral malignant melanoma is uncommon, comprising less than 1% of all malignant melanomas. Consequently, few cases have been reported from any one institution. We report 10 cases of malignant melanoma of the oral cavity seen at the Mayo Clinic between 1905 and 1979. The site of the primary tumor was the hard palate in 4 patients, the soft palate in 2 patients, the lower alveolus in 2 patients, and the upper alveolus and the retromolar trigone in 1 patient each. Eight of these tumors occurred in men, and 8 patients were older than 60 years of age. Presenting symptoms were a pigmented mass in 9 patients, pain in 5 patients, and bleeding in 3 patients. In 4 patients, the tumor occurred in an area of preexisting hyperpigmentation. The treatment of choice in this disease is surgery; it is the only form of therapy with curative potential. Radiation therapy produced tumor regression in one patient in whom the tumor was considered inoperable, although there was no effect on eventual survival. Chemotherapy was ineffective in producing tumor regression. The prognosis of patients who have malignant melanoma of the oral cavity is dismal; the median survival time in this series was 16 months after diagnosis. Early diagnosis of pigmented lesions in the mouth and adequate tumor resection may improve the prognosis in this disease; however, once the tumor recurs, there is essentially no possibility of prolonged survival.