A 50-year-old Japanese housewife became blind owing to bilateral diffuse malignant melanoma of the choroid, ciliary body, and iris. These were histologically proved when enucleation was required because of blind painful eyes with raised intraocular pressures. She presented with reduced visual acuity and night blindness. Small scattered atrophic areas were observed between disc and macula on both sides, which fluorescein angiography showed were due to patchy atrophy of the retinal pigment epithelium. There was reduced amplitude in the electroretinogram. Inferior retinal detachments soon appeared and spread to become total. Pathological examination showed diffusely thickened choroid on both sides, due to infiltration by epithelioid and spindle-shaped malignant melanoma cells, which also affected the thickened ciliary body and iris diffusely. A carcinoma of the uterus successfully treated three years previously and the probably multicentric origin of the malignancy in each eye, and its bilateral occurrence, suggest a tumour-producing tendency in this patient, an interpretation which also applies to one of the other eight reported cases.