Background and Aim: Melanoma is a malignant neoplasm of melanocytic origin that arises from a benign melanocytic lesion or denovo from melanocytes within otherwise normal skin or mucosa. Oral mucosal melanoma is much less than %1of all melanomas. Mucosal melanoma is much more aggressive than its cutaneous counterpart. Due to a real increase in the frequency of melanoma in recent years, we investigate the prevalence of malignant melanoma in the mouth ,head and neck during a 11 years period in Iranian population. 

Materials and Methods: This study was done on the pathology records of patients admitted to the Department of Pathology, School of Dentistry Shahid Beheshti ,Lughman Hakim, Shohada,Taleghani hospitals and Institute cancer of Imam Khomeini. In this study the variables like gender, age, location of the lesion, recurrence and metastasis was evaluated. The chi-square test was used to analyze information obtained from the research. 

Results: Of the 191679 cases accessed during the 11-year period, 262(0.14%) were identified as oral& maxillofacial malignant melanomas. The average age of melanoma was 50+-11/01years and the incidence in men was higher than women. The most common clinical feature was discoloration (46.9%)and then was ulceration (18.6%).Of all cases 24.8% had metastases. The most common site was the neck and cheek, and the most common area in the mouth, was reported in palate. 

Conclusion: Frequency of head and neck melanoma was 0.14% of all studied cases. The most common and the least common sites were neck and chin, respectively. Most cases of oral melanoma were localized in the palate and the incidence in men was higher than women. 

Key words: Frequency, Melanoma, Malignant, , Oral Cancer