Some cases of malignant melanoma of the choroid pose little or no problem in diagnosis. However, in other cases, after all available diagnostic procedures have been used, only a presumptive clinical diagnosis can be made. The decision for enucleation then must rest on clinical judgment and consideration of the risk involved in watchful waiting, especially in an eye with useful vision. To discover clinical criteria which might be of help in making a differential diagnosis, a survey was made of the melanomas received at the pathology laboratories at the Illinois Eye and Ear Infirmary and the Research and Educational Hospitals of the University of Illinois. The clinical descriptions were studied, and an attempt was made to correlate them with the histologic picture. Those cases in which the eye was enucleated because of the possibility of a melanoma and in which, on histologic examination, no tumor was found, will be presented