Patients who are diagnosed initially as having metastatic melanoma with no known cutaneous, mucosal or ocular primary are a perplexing clinical problem. In the Duke University Melanoma Clinic, 124 patients have been identified as meeting the criteria of an unknown primary melanoma. This represents 4.8 per cent of the total melanoma population seen at this institution. There were 2.5 times as many males as females with an average age at diagnosis of 47.9 years. Regional lymph node disease was the most common presentation with 64 per cent of the patients falling into this category. Those patients who showed initial evidence of hematogenous spread of their melanoma had a worse prognosis than their counterparts who manifested primarily lymphatic spread. When compared with control population groups with known primary melanoma, the unknown primary group had equal survival emphasizing that surgical treatment should be similar for both groups.