Two homosexual males with the "gay bowel syndrome' experienced an acute unilateral loss of vision. Both patients had white intraretinal lesions, which became confluent. One of the cases had a depressed cell-mediated immunity; both patients ultimately died after a prolonged illness. In one patient cytomegalovirus was cultured from a vitreous biopsy. Autopsy revealed disseminated cytomegalovirus in both patients. Widespread retinal necrosis was evident, with typical nuclear and cytoplasmic inclusions of cytomegalovirus. Electron microscopy showed herpes virus, while immunoperoxidase techniques showed cytomegalovirus. The altered cell-mediated response present in homosexual patients may be responsible for the clinical syndromes of Kaposi's sarcoma and opportunistic infection by Pneumocystis carinii, herpes simplex, or cytomegalovirus.