Etiological characteristics of endogenous uveitis vary among areas and races around the world. There are few epidemiological reports on the etiology of uveitis from areas within Asia. We report statistical data on uveitis in Japan. We reviewed all of the records of patients with endogenous uveitis who visited the Uveitis Survey Clinic of Hokkaido University Hospital in 1981 and 1994 and extended the survey to include new patients with uveitis seen over the 3-year period from 1992 to 1994. Bechcet's disease, sarcoidosis and Vogt-Koy-anagi-Harada disease were the three most frequently diagnosed diseases in both 1981 and 1994. The proportion of patients with unclassified uveitis decreased from 38% to 30% during the 13-year period from 1981 to 1994 as a result of the establishment of new disease categories during this time. Notable additions included human T-lymphotropic virus type 1-associated uveitis and tubuloinerstitial nephritis and uveitis syndrome. Sarcoidosis is now the most frequent endogenous uveitis in our clinic. Not only does the etiological basis of uveitis vary among ethnic groups but advances in clinical and basic research have changed the diagnostic approach to uveitis, altering the etiological profile over time.