We report a 73-year-old man with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM) complicated with multi-organ inflammatory disease, including Sjögren's syndrome, interstitial cystitis, and uveitis. The presence of HTLV-I proviral DNA in peripheral blood mononuclear cells (PBMC), cerebrospinal fluid, salivary gland, mucosa of urinary bladder, and aqueous humor was confirmed by polymerase chain reaction using HTLV-I pX region primer. Western blot analysis revealed the presence of anti-HTLV-I antibodies in serum, CSF, saliva, and urine, suggesting replication of HTLV-I in each tissue. A high load of HTLV-I proviral DNA (20 copies out of 100 PBMC) was present, associated with increased spontaneous proliferation of peripheral blood lymphocytes (24,747 cpm). Our results suggest that the high load of HTLV-I in patients with HAM may potentially induce systemic inflammation in several organs.