A consecutive series of 34 patients with HTLV-I-associated myelopathy (HAM), a neurological disease associated with human T-lymphotropic virus type I (HTLV-I), were studied with reference to endogenous ocular disorders. These patients were examined at the Kagoshima University Hospital between 1986 and 1988. Five of the 34 HAM patients showed noninfectious, granulomatous anterior uveitis responding to corticosteroid therapy and/or retinal microvascular changes such as isolated cotton-wool spots; one of the patients had recurrent uveitis. Additionally, twelve of 30 patients who had been infected with HTLV-I but remained healthy systemically had ocular manifestations similar to those in HAM patients were included in this study. The ocular lesions in these patients were not explained by any established disorders that manifest uveitis or retinal microangiopathy. Some of the HTLV-I-seropositive patients with ocular disorders showed antibodies against HTLV-I in the aqueous humor. This might have resulted from diffusion of serum antibodies through a damaged blood-aqueous barrier or local synthesis of antibodies. The HTLV-I infection might be primarily responsible for a certain form of endogenous anterior uveitis that has remained hitherto etiologically undefined.