In an eye with a proton beam-irradiated malignant melanoma of the ciliary body a second melanoma appeared episclerally on the opposite side of the globe. Microscopic examination did not show any connection to the primary tumor. The different possibilities of pathogenesis (bloodborn metastasis to the same globe, episcleral metastasis by conjunctival lymphatics, surgical dissemination due to the suturing of tantalum marks around the primary tumor) are discussed. The ciliary melanoma has spread over the iris despite the irradiation, probably as a result of insufficient irradiation of its anterior border. The results of histologic examination of the partially necrotic, partially viable irradiated tumor are considered with regard to the conservative tumor therapy administered.