We have reviewed the clinical and pathologic findings of 25 patients with the acquired immunodeficiency syndrome (AIDS) who had a complete post-mortem examination including a study of the nervous system and of one or both eyes. Cytomegalovirus (CMV) retinitis was the most frequent type of ocular infection observed fundoscopically (9 of 18 cases examined clinically). There were only 3 cases of CMV encephalitis amongst the 8 cases of CMV retinitis documented pathologically. Cerebral toxoplasmosis was found in 12 of the 25 cases and in only one of these could Toxoplasma gondii cysts be demonstrated in the optic nerve. Cotton wool spots were the most frequent lesion observed fundoscopically (10 of 18 cases examined clinically). In the 3 cases where they were observed microscopically they corresponded to cytoid bodies which represented axonal swellings within the nerve fiber layer. The pathogenesis of this lesion in patients with AIDS is not understood. Intraocular lymphoma was present in only one case.