Primary oral melanoma (POM) is a rare form of melanoma, generally diagnosed at a late stage and has poor prognosis. Epidemiological information has scarcely been reported in the literature over the past 40 years. Analyzing the Cancer Incidence in Five Continents volume IX (CI5-IX) database we found a total of 124,436 oral cavity cancers reported from all population-based cancer registries and 319 cases of POM reported by 67 cancer registries. To our knowledge this is the largest number of POM cases analyzed and accounts for 0.26% of all oral cavity cancers. ASR(W) for POM do not exceed 0.01 per 100,000 persons-year in all regions. The most common anatomic sites were palate (47%) and gum (27.6%) and a detailed oral mucosa examination and biopsies of nodular or macular lesions in these sites, especially on elderly patients, is advised to be routinely performed. (C) 2008 Elsevier Ltd. All rights reserved.