We studied the case records of 1122 patients with endogenous uveitis including 418 new cases treated at the University Eye Clinic in Turku during the years 1980-1982 and 1988. The mean annual incidence and prevalence rates (per 100,000 population) of idiopathic acute anterior uveitis were 17.1 and 48.5, respectively, sarcoid anterior uveitis 0.5 and 1.5, Posner-Schlossman syndrome 0.4 and 1.9, herpes zoster uveitis 0.4 and 0.7, idiopathic chronic anterior uveitis 0.3 and 7.3, herpes simplex keratouveitis 0.3 and 0.5, juvenile rheumatoid arthritis 0.2 and 2.4, Fuchs' heterochromic iridocyclitis 0.2 and 0.5, intermediate uveitis 0.3 and 1.4, and of toxoplasmic retinochoroiditis 0.3 and 2.4. The incidence and prevalence rates of acute anterior uveitis associated with ankylosing spondylitis were 2.0 and 10.3 per 100,000 population, respectively, and this disease association occurred more often in men than in women (p < 0.001). The mean annual incidence of idiopathic acute anterior uveitis was significantly lower in the age group 0-19 years than in the other age groups (p < 0.001).