We determined the antibody response against Borrelia burgdorferi strains isolated from Japanese Ixodes ovatus and Ixodes persulcatus ticks by enzyme-linked immunosorbent assay and indirect immunofluorescence assay of serum specimens from 127 patients with uveitis. We examined samples of serum from Japanese patients with unclassified uveitis, iridocyclitis caused by herpes zoster virus, Behçet's disease, Vogt-Koyanagi-Harada syndrome, sarcoidosis, or other conditions (sympathetic ophthalmia, Posner-Schlossman syndrome and acute anterior uveitis with ankylosing spondylitis). Serum from healthy individuals and patients with Lyme disease served as negative and positive control samples, respectively. Significantly higher antibody titers were demonstrated in patients with uveitis than in control subjects. Of 29 patients with unclassified uveitis, nine (31) had significantly increased antibody titers against B. burgdorferi strain H014 by ELISA testing. Five patients also showed higher IgG and IgM responses than in three control subjects with Lyme disease. All positive controls showed joint problems characteristic of rheumatoid arthritis. One of three patients had uveitis. The patients were diagnosed as having Lyme disease on the basis of their history and serologic tests. A positive antibody response was recognized in several patients with Behçet's disease, Vogt-Koyanagi-Harada syndrome, sarcoidosis, and other conditions (acute anterior uveitis with ankylosing spondylitis), but not in control subjects.