The possible association of Epstein-Barr Virus (EBV) with uveitis was investigated in 28 subjects with various types of uveitis. Serum or aqueous humor (AH) EB viral antibodies were measured in 28 uveitis patients and in 28 cataract patients as controls. Significant rises in EBV antibody levels were seen in 3 cases from the uveitis group. There was an 8-fold increase of the serum antibody titer in an infant subject, a 16-fold increase in the AH EB viral antibody titer in an adult subject, and a higher antibody quotient (10.2) compared with the serum and AH antibody titers in another adult case. No antibodies to EBV were detected in the AH in the control group. It appeared that EBV might have been involved in the pathogenesis of these 3 cases of uveitis. The clinical features of these cases were as follows. (1) A common cold-like prodrome was noted. (2) Severe acute anterior uveitis with fibrinous exudate was present at the onset. (3) A transition to chronic granulomatous anterior uveitis was seen in the 2 adult cases. (4) Little vitreous inflammation was present. (5) Marked hyperemia and swelling of the optic discs was noted. (6) At the onset there were no abnormal chorioretinal findings, except slight retinal vasculitis in the infant case. (7) Sunset-glow fundus appeared earlier in comparison with Harada disease in the adults and a retinal pigment epithelium disorder developed in the infant. (8) Bilateral involvement was seen in adults. (9) Good final visual acuity was recognized. (10) No systemic changes occurred in the course of the uveitis. This constellation of clinical features appears to comprise a new entity, i.e., EBV-associated uveitis.