Thirty-one recipients of cadaver kidney transplants were given OKT3 monoclonal anti-T cell antibody for rejection treatment after conventional therapy had failed. Seventy-four percent of steroid or steroid and antithymocyte globulin (ATG) resistant rejections reversed with a standard course of OKT3. Rejections reversed in 85% of 26 patients treated within 90 days of transplantation. Late rejections treated more than 90 days after transplantation were poorly responsive to OKT3 and graft survival for this group of five patients was poor (20%). However, for those patients treated with OKT3 for early resistant rejection, actuarial 4-year graft survival was 66%. Actuarial 4-year patient survival was 97%, and the incidence of serious infection was low. Acute rejections in cadaver transplantation are common and a small percentage of rejections are resistant to steroids and ATG. OKT3 has proven to be useful for reversing these resistant rejections without causing significant morbidity from infection or death.