We present our observations on the use of cyclosporine in the treatment of three patients with mycosis fungoides and two patients with Sézary syndrome. The patients with mycosis fungoides showed mild improvement of short duration. One patient with Sézary syndrome had significant improvement during 2 years of treatment. It is unlikely that cyclosporine alone will be sufficient therapy for cutaneous T cell lymphoma. However, lower doses in conjunction with other immunomodulators may minimize potential side effects and lead to longer lasting clinical improvement.