Two previously unreported patients with cutaneous T cell lymphoma associated with systemic low-grade B cell proliferations are presented. The first patient had Waldenström's macroglobulinemia and the second had simultaneous chronic lymphocytic leukemia. The use of immunosuppressive drugs or a genetic predisposition may have contributed to the second malignancy. However, the possibility that malignant helper/inducer T lymphocytes were a factor in the promotion of the proliferation of B cells cannot be excluded.