This paper describes attempts to produce uveitis in guinea pigs by using heterologous lens protein and serum antibodies to heterologous lens and uvea. 1. 1. Only a mild uveitis was produced by extraocular means. 2. 2. The most successful experimental procedure was intravitreous injection of lens protein into an animal sensitized to lens with the use of adjuvant. 3. 3. The injection of guinea pig sera containing heterologous precipitins and complement-fixing antibodies to bovine lens and uvea into the anterior chamber of animals failed to excite any uveal response. Intravitreous injection produced a mild reaction in one of five animals.