A 79-year-old woman had cutaneous T cell lymphoma. After a long clinical course, numerous tumors and an enormous increase in peripheral granular lymphocytes without lymphadenopathy developed suddenly. Surface markers and DNA analysis of the tumor cells from her skin and peripheral blood and electron microscopic examination suggested that granular lymphocytic leukemia had developed in the terminal stage of cutaneous T cell lymphoma. To our knowledge this association has not been reported previously.