An enzyme linked immunosorbent assay was developed for the detection of immunoglobulin class specific antibodies toLeptospira interrogansserovarpomonain the serum and aqueous humor of horses. Serum antibody was also assayed by microscopic agglutination tests.Although higher levels of antibody were found in sera from horses with signs of uveitis, the association was not statistically significant. Antibodies topomonawere detected in the aqueous of 12 eyes from the 101 horses sampled at a slaughterhouse, and in most instances, a comparison of the aqueous/serum antibody level with that of the total aqueous/serum IgG level indicated intraocular antibody synthesis. Antibodies were also found in 4 aqueous (or vitreous) samples out of 9 obtained from horses with clinically documented uveitis and the above comparison again indicated intraocular antibody synthesis.The data point to an important role forpomonaas an etiology of equine recurrent uveitis but also emphasize that the initiating cause for this disease is often obscure in that association with leptospirosis cannot be shown in many instances.