The clinical features of human T-lymphotropic virus type (HTLV-I) uveitis, an idiopathic uveitis in HTLV-I seropositive patients, were analyzed in a hospital located in an area where HTLV-I was endemic (Miyakonojo, Miyazaki). A total of 61 patients (25 males and 31 females) with HTLV-I uveitis were the subjects of the analysis. Intermediate uveitis with moderate to severe vitreous opacities accompanied by mild iritis and retinal vasculitis was the most characteristic feature, and was observed in the majority of the patients (66% of all or 84% in young adult patients between 20 and 49 years of age). The uveitis affected one eye in 57% and both eyes in 43% of the patients, with subacute onset of floaters and foggy vision. The uveitis responded well to therapy with topical or systemic corticosteroids, but recurred in many cases. A significant number of patients (15% of all and 25% of female patients) had a previous history of Graves' disease with hyperthyroidism.