Partial tumoral responses have been described after cyclosporin A treatment in refractory B-chronic lymphocytic leukemia patients. We report the effect of this therapy in five patients prospectively treated with oral conventional dose of cyclosporin A. Antitumoral efficiency was marginal (one sustained partial response among five patients) which, added to a potential worsening of natural and therapy-related immunodepression, limits its use in this instance.