A malignant ciliary body melanoma was treated by proton-beam irradiation. Ring-shaped recurrence with extraocular extension appeared thirty-six months later and required enucleation. Histologic study revealed a predominant epithelioid cell type tumor, flattened in previously treated area. Proton-beam irradiation efficiency depends on clinical evaluation, which remains questioned in ciliary body locations where circumferential extension could be misevaluated.