The prognosis of immunoblastic lymphadenopathy (IBL)-like T-cell lymphoma is grave, and its effective treatments have not been established. We applied oral cyclosporin A (CsA) treatment to two cases of IBL-like T-cell lymphoma, and succeeded in achieving complete remissions. CsA is known to have a suppressive effect on the immune system, most notably T-cells, but it also has a direct cytotoxic/apoptosis-inducing effect on lymphocytes. Its combined effects on neoplastic T-cells might have played an important role in achieving remission. In both cases, serum levels of interleukin-12 (IL-12) and tumor necrosis factor-alpha (TNF-alpha) were elevated and decreased or returned to normal after achieving remissions. Considering that both cytokines represent monokines, it seems that a macrophage system is also involved in the pathogenesis of this disorder. Our two cases indicate that administration of CsA may be an effective therapy for IBL-like T-cell lymphoma.