A retrospective study on 1,417 uveitic patients referred to the Ocular Immunovirology Service of the University of Rome 'La Sapienza' was carried out to determine the occurrence of the various forms of uveitis. To detect also the possible changing patterns of uveitis during the last 25 years the obtained data were compared with those reported in two previous studies performed by the same author, at the same institution in 1978 and 1985. Anterior uveitis was the most frequent anatomical type of intraocular inflammation (49.12%); intermediate uveitis was diagnosed in 12.42% of all the cases and showed an increased incidence over the years (p < 0.0001). Posterior and diffuse uveitis accounted for 22.1 and 16.37% of the cases. An improvement in diagnostic definition has been confirmed by the significant decrease in the percentage of 'idiopathic uveitis' from 56.8 to 38.1% (p < 0.0001). Associated infectious conditions were detected in 17.43% of the cases. Toxoplasma gondii was the most common etiologic agent of uveitis (6.63%). An associated systemic disease was diagnosed in 15.03% of uveitic patients, and 6% of them were affected with Behçet's disease. Specific ocular diseases and clinical entities increased from 7.8 and 14.68% to 29.42% in the last 25 years (p < 0.0001), the most frequent being pars planitis (11.99%) and Fuchs' heterochromic iridocyclitis (8.32%).