One hundred and sixteen patients with retinitis pigmentosa (RP), 64 patients with other eye diseases, and 36 control subjects with no known eye disease were examined for antiretinal autoimmune activity. Sera were screened by indirect immunofluorescence on normal donor human eye sections to detect antibodies to human retinal antigens. Forty three of 116 RP patients (37%), 21 out of 64 non-RP patients with other eye diseases (33%), and 1 out of 42 controls (2%) had antibodies reacting with donor eye retinal antigens. Lymphocytes were tested by an in vitro transformation assay to detect cell mediated immunity to retinal antigens. Sixteen RP patients (19%), 11 non-RP patients (18%), and four controls (10%) showed lymphocyte sensitisation. Autoimmune responses were detected in many degenerative ocular disorders, but it is not known if they play a contributory pathogenic role.