A 42-year-old-woman, with a 2 year history of non-Hodgkin's lymphoma suffered sudden bilateral visual loss. This unusual patient presented with an unifocal choroidal tumor in the superionasal quadrant in both eyes. Fluorescein angiography revealed early and late intense subretinal fluorescence. Cytological examination of the anterior chamber and vitreous tap material revealed abnormal lymphocytes compatible with NHL. Diffuse choroidal infiltration was diagnosed and treated with radiotherapy. Radiotherapy did not provide local control and preservation of the vision. Non-Hodgkin's lymphoma can infiltrate to the choroid and radiotherapy may not be efffective in every case.