Oral malignant melanoma of the oral cavity is rare. Although the Asian population has a relatively high incidence of oral malignant melanoma in contrast to Caucasians, the clinical information in Korean has been rarely known. In addition, the clinical and histological classification of oral malignant melanoma has not been established up to now. So we investigated 26 cases of oral malignant melanomas on the basis of clinicopathological and immunohistochemical findings and reclassified the clinical and histological type. The results of this study are as followed. Oral malignant melanomas occurred at any age from 28 years to 73 years and their mean age was 58.6 years. Of 26 cases, 14 occurred in male and 12 in female. Oral malignant melanomas occurred almost in palate and/or maxillary gingiva (25 cases; 96.2%). Only one case occurred in mandibular gigiva. Oral malignant melanomas were clinically divided into macular(9 cases) and nodular type(17 cases), showing that the nodular type occurred more frequently. Oral malignant melanomas were histologically divided into in situ spreading(5 cases), invasive(13 cases), and combined type(8 cases), showing that the invasive type occurred most frequently. All cases showed positivity for S-100 and 15 cases(57.7%) for HMB-45 in immunohistochemical analysis. It was thought these results could provide basic data for the research on oral malignant melanoma in Korean and additional prospective and retrospective studies would be needed in order to find the relations with the prognosis of the patients