Choroidal malignant melanoma was diagnosed on pathologic examination of enucleated globes from a 54-year-old man and his 58-year-old sister. The brother had been monitored at four-month intervals for four years because of a choroidal lesion, which abruptly increased in size, in his left eye. Three years after an examination with normal findings, the sister developed a retinal detachment with a pigmented dome in her right eye. Both patients are doing well five years (Patient 1) and two years (Patient 2) after enucleation. Screening examinations detected two cases of benign melanoma (nevi) in 18 close relatives but this incidence did not exceed chance.