Preparations of allogenous and xenogenous retinal rod outer segments (ROS) were found to be adequately antigenic for detection of cellular immunity in human chorioretinitis. The electrophoretic mobility test was used for estimation of delayed-type hypersensitivity. No significant results with ROS were found in patients with panophthalmia or in control subjects. It is assumed that the results reported here in chronic ophthalmic inflammation may be produced by or connected with autoimmune processes.