Primary malignant melanoma is rarely found in the oral cavity (1,7% of head and neck melanomas) and occurs more frequently in the sixty decade of life. In this paper, the authors related a case of malignant melanoma in the mouth of a 35-year-old black female, who was originally diagnosed by a dentist as a simple racial hyperpigmented lesion. An inferior maxillectomy was performed and the patient was submitted to a therapy with alpha interferon and radiotherapy. There were two recurrences over a year and a half follow-up period. The authors made a review of the literature about primary malignant melanoma in the head and neck, discussing diferential diagnosis and therapeutic possibilities, concluding that in many cases the diagnosis of melanoma is made from the pre existing pigmented lesion of undetermined origin which must be biopsed as a routine. The prognosis is often poor and the surgical approach must be combined with chemo and/or radiotherapy.