A case of chronic adult T-cell luekemia (ATL) complicating disseminated strongyloidiasis was reported. A 64 year-old woman born in Nagasaki prefecture, was admitted in our hospital because of arthralgia and skin rash in April, 1984. The luekocytes counts were 52,100/cmm with 75% of abnormal lymphocytes, their surface marker showed OKT3; 3.6%, OKT4; 98.4%, OKT8; 0.8%. Anti-ATLA antibodies was positive. Serum LDH elevated but no hypercalcemia and no hepatosplenomegaly were showed. The diagnosis of chronic ATL was made. One year after diagnosis, clinical symptoms and hematoligical findings were gradually progressive. Treatments of α-Interferon, total body irradiation and lymphaphersis were done. She complained of dyspnea in April, 1986. The findings of interstitial-pneumonitis revealed in chest X-ray, and ATL cell-infiltration was difined by TBLB specimen. Progression of skin rash and lymphadenopathies were observed, the diagnosis of acute crisis of chronic ATL was made. The treatment of VEPA was slightly effective. Bloody stool appeared in 9 June, 1986. Strongyloides were positive in stool and sputum. Mintezol therapy poorly responded. She died 16th days after the diagnosis of disseminated strongyloidiasis. The causes of death were suspected septic shock and DIC.