A case is presented of an intraocular T-cell lymphoma mimicking a ring melanoma of the iris and being the first manifestation of systemic disease. A 51-year-old woman was referred with an anterior uveitis, initially presenting as a granulomatous iritis. Nodules had developed in the circumference and the lesion now imitated a malignant melanoma of the iris, which was also the diagnosis from a biopsy specimen with routine staining. Clinical, haematological and serological examination revealed no other symptoms or signs. Lymphocytic markers applied to the biopsy specimen and to the enucleated eye revealed a highly malignant T-cell lymphoma infiltrating the iris, ciliary body, anterior choroid, retina and the adjacent vitreous body. Further examination later showed T-cell lymphoma in the bone marrow, the only other organ involved. The patient died in a leukaemic phase about 1 year after the first admission. Previous cases of T-cell lymphoma with ocular involvement are reviewed.