Mucosal malignant melanoma (MMM) of the nasal cavity and paranasal sinuses is rare and has a poor prognosis. The rarity of MMM of the ethmoid is also noteworthy and primary treatment has been, till now, surgery and/or radiotherapy (RT). Here we report a case of MMM arising in the ethmoid of a caucasian man and treated with hypofractionated RT. A 32 year-old man presented with symptoms of cephalalgia, obstruction and nasal bleeding; a computed tomography (CT) showed a large mass that involved ethmoid, left orbit and roof of the nasal cavity. After biopsy, a MMM was found. Chest radiography demonstrated the presence of multiple lung metastases and still the patient was submitted to palliative radiotherapy according to 0-7-21 regimen with a total dose of 24Gy/3 fraction/21dd, dose per fraction 8Gy. The patient was asymptomatic one month after the end of RT and three months later a CT demonstrated a partial remission. The patient died 17 months after the initiation of RT for disseminated disease, without clinical signs of tumoral regrowth in the irradiated site. This case confirms the efficacy and the safety of 0-7-21 RT regimen; the absence of symptoms after 17 months and the poor prognosis encourage the use of RT as primary treatment for MMM of the head and neck.