BACKGROUND The nomenclature and the clinical and pathologic features of cutaneous and conjunctival melanomas are different. A comparison is made to familiarize dermatologists and ophthalmologists with these differences. METHODS Five cases of conjunctival malignant melanoma from December 1983 to December 1990 were reviewed. RESULTS The nomenclature of primary acquired melanosis is not used for cutaneous melanomas, and terms such as dysplasia and Clark's nevus are not used for conjunctival melanomas. Technical difficulties exist in orienting thin conjunctival tissues because of a tendency to curl during fixation, resulting in tangential sectioning and making a false diagnosis of a prognostically ominous pagetoid spread for an otherwise banal basilar hyperplastic pattern. Excision, cryotherapy, and rarely exenteration are the therapeutic measures in managing conjunctival melanomas; these have far more serious consequences for the patient compared with the excision of a skin melanoma. CONCLUSIONS Differences exist in several aspects between melanomas located in the skin and the eye.