Malignant melanoma is a neoplasm of melanocytic origin that arises from a benign melanocytic lesion or de novo from melanocytes within otherwise normal mucosa or skin. Melanoma arising from the mucosal surfaces of the head and neck is a very rare disease and is considered among the most deadly of all human neoplasms. Although it comprises 1.3% of all cancers, malignant melanoma of the oral cavity accounts for only 0.2% to 8.0% of all reported melanomas. Because most mucosal melanotic lesions are painless in their early stages, the diagnosis is unfortunately often delayed until symptoms resulting from ulceration or growth are noted. Oral malignant melanoma has an extremely poor prognosis. For prevention of oral mucosal melanomas, any solitary pigmentation that has no obvious explanation should be always biopsied. The case of a 40-year-old man with primary malignant melanoma of the maxillary gingiva is reported. Keywords: melanocytes, oral malignant melanoma, pigmented areas