Four major double-blind randomized trials in kidney transplant patients have shown that the interleukin-2 receptor (IL-2R alpha) antagonists declizumab or basiliximab, when added to an immunosuppressive regimen consisting of cyclosporin and prednisone, reduce the incidence of acute rejections after kidney transplantation by 30-40%, during the first 6 months. Daclizumab and basiliximab are monoclonal antibodies of which the variable parts are of mouse origin and the other components of human origin. The addition of the interleukin-2 receptor antagonists was not accompanied by extra side effects. Ongoing clinical trials aim at answering the question whether the addition of daclizumab and basiliximab will allow to avoid or decrease the use of more toxic immunosuppressive drugs.