We reviewed 293 cases of choroidal and ciliary body melanoma with a followup period of five years or more. Nine factors influenced significantly the prognosis: Age of the patient at the time of enucleation, location of the tumor and of its anterior border, largest tumor diameter in contact with the sclera, height of the tumor, integrity of the Bruch membrane, cell type, pigmentation, and scleral infiltration by tumor cells. Some of these factors can be evaluated clinically before the enucleation. Seven sets of three factors each were determined in order to have better prognostic values based on the clinical data and the cell type. The largest tumor diameter is the single most important clinical and pathological prognostic factor. The prognosis is relatively good when this diameter is 10 mm or less and becomes poor when it exceeds 10mm.