BACKGROUND Mucosal melanoma of paranasal sinuses is a rare disease with a challenging treatment and a poor prognosis. In this paper, we reported the successful multimodality treatment of malignant mucosal melanoma of frontal sinus. METHODS A 65-year-old female presented with a frequent nosebleed for one month before admission. Computed tomography and magnetic resonance imaging showed a mass in the right frontal and ethmoidal sinuses with adjacent bone erosion and right orbit invasion. Biopsy revealed malignant melanoma. No metastasis was found. The definitive diagnosis was malignant mucosal melanoma of paranasal sinuses AJCC stage IVb (T4bN0M0). We used right frontobasal craniotomy to resect tumor for local control of the disease. Immunohistochemical staining was Melan A(+), S100(+), and HMB45(+). A week postoperative, she received adjuvant radiotherapy and immunotherapy (pembrolizumab). For three months postoperative, the patient had no recurrence and metastasis, no headache and no new neurological deficits. She returned to her daily activities. Mucosal melanoma of paranasal sinuses is usually aggressive and diagnosed at an advanced stage. Management options are surgery, radiation therapy, chemotherapy, and immunotherapy. These options were performed on a case-by-case basis and depend on the extent and location of the tumor. Despite that, the prognosis remains very poor, with a high rate of local recurrences and distant metastases. Therefore, post-treatment lifetime and frequent follow-ups are highly recommended. CONCLUSIONS The critical issues in management of mucosal melanoma are early diagnosis, multimodality treatment, and frequent follow-ups.