The HTLV-I infection was endemic in south western Kyushu. This human T-lymphotropic virus type I may cause HTLV-I associated myelopathy (HAM), a neurological disease characterized by a spastic paraparesis. And one of the minor diagnostic features of HAM is the presence of cystorectal disturbance. We experienced 35 HAM patients with a neurogenic bladder. A gradually progressive contracted bladder was observed in 3 of them. The main pathological finding in these patients was submucosal infiltration of lymphocytes. These findings suggest that immunologic mechanisms account for the development of bladder lesions.