Leukocyte migration inhibition (LMI) by choroid, retina, and uveal tract antigens was studied in patients with active and quiescent chorioretinal disease. LMI by retina was more frequent in both groups of patients, occurring in 9 of 16 patients with active disease and in 8 to 15 patients with disease in remission. Choroid was tested in 15 patients with active inflammation and led to LMI in 7 of them when they were off steroid therapy; it produced LMI in 3 of 13 patients whose disease appeared healed. Significant LMI was detected in three of six patients with active chorioretinitis and in one of five patients with evidence of past chorioretinopathy when their cells were tested with antigen made from pooled uveal tract tissue. The LMI test, regarded as an indicator of cell-mediated immunity, is briefly discussed. LMI by retina in over one-half of patients with chorioretinopathies appears to be a secondary event, and cellular immunity to retina may be of pathophysiological importance in the chronicity of the disorder.