In many instances enucleation of an eye that is erroneously thought to contain a malignant melanoma is a tragic loss for the patient. In a recent retrospective study it was shown that 19% of eyes removed because of a diagnosis of malignant melanoma of thechoroid or posterior ciliary body, on the basis of an ophthalmoscopically visible lesion, were found on pathologic examination1to harbor a lesion other than malignant melanoma. The rather startling observation that one in every five eyes with an ophthalmoscopically visible lesion diagnosed clinically as malignant melanoma proves to be an instance of erroneous diagnosis led us to investigate the incidence of incorrect clinical diagnosis in the case of malignant melanoma of theiris. These tumors are less common than malignant melanomas of the ciliary body and choroid, and the clinician has even less experience in dealing with them than with those that involve the