Four patients had malignant melanoma involving the conjunctiva, nasal cavity, and paranasal sinuses. In each patient, the conjunctival melanoma preceded recognition of the lesion in the nasal cavity by months or years. Each patient had one or more conjunctival biopsy specimens that documented melanoma, and in each patient the melanomas evolved in primary acquired melanosis of the conjunctiva. Histologic examination of the epithelium adjacent to the tumor in the nasal cavity failed to show either atypia or diffuse melanosis. We believe that these melanomas in the nasal cavity and paranasal sinuses are most likely to evolve as regional metastases, although it is possible that they arise de novo or as related foci in accordance with the multicentric characteristics of conjunctival melanoma. If a patient with a conjunctival melanoma has symptoms referable to the nasal cavity or paranasal sinuses, ophthalmologists should refer the patient to an otolaryngologist.