The effect of antigenic competition on the development of autoallergic experimental uveitis and autoallergy to ocular antigens was studied. Strain 13 guinea pigs were immunized with adjuvants containing either National Institutes of Health strain retina-uvea extract or retina-uvea extract plus bovine gamma globulin (BGG). They were later reimmunized with ocular extract and BGG or ocular extract alone, in adjuvant. They were observed weekly by slit-lamp examination. At the end of the study, they were skin tested using strain 13 retina-uvea extract. The eyes of certain groups were examined histologically. Immunization and reimmunization with ocular extract produced uveitis. The addition of BGG to the initial immunization prevented the development of uveitis even after reimmunization with ocular extract alone. It did not, however, necessarily prevent the development of delayed type skin sensitivity to retina-uveal extract.