We reviewed 188 patients with chronic vitreous inflammation initially diagnosed as intermediate uveitis, who were seen at the Ghent Eye Clinic during the period 1978 to 1988. We were able to establish a more specific diagnosis in 55 patients. The different approaches that contributed to the diagnosis were analyzed, (comprehensive history-taking and clinical examination, laboratory tests and special investigations, vitrectomy, and following the evolution of the disease). No etiology was found in 133 patients (70.7%), subsequently diagnosed as idiopathic intermediate uveitis. The major characteristics of the disease were analyzed.