A patient with triple malignancies is reported, who presented cervical cancer, vulvar cancer and adult T cell leukemia (ATL). ATL was diagnosed as a smouldering type, because antibody to human T cell leukemia virus associated antigen (ATLA) was positive with a titer of 1:160. Although her malignant cells had an OKT 4+8-3+Tac+ phenotype, the cells did not display helper T cell functions. Namely they showed no response to Phytohemagglutinin (PHA) and Interleukin 2 (IL-2) and suppressed the PWM driven IgG synthesis of B cells obtained from healthy donor. They did not produce IL-2 by stimulation with PHA and phorbol myristate acetate (PMA). Furthermore, these ATL cells were producing IL-2 inhibitor like factors. As synchronous triple malignancies are extremely rare, two gynecologic cancers seem to ascribe to the suppressing state of the immunosurveillance mechanism by viral infection.