Decreased 1-year allograft survival rates have frequently been observed in cadaveric renal allograft recipients with postoperative acute tubular necrosis (ATN), even in the cyclosporine era. Use of cyclosporine despite ATN may lead to a prolongation of ATN, while withholding cyclosporine may increase the chance of an early rejection episode. Prophylactic polyclonal antilymphocyte antibodies have been used postoperatively to prevent rejection while avoiding cyclosporine nephrotoxicity. Since January 1987, the authors have used OKT3 monoclonal antibody prophylaxis in all cadaver kidney recipients with ATN (n = 26). The posttransplant course of these patients was compared with that of cadaveric kidney recipients with ATN who received transplants in 1985-1986 and were treated with cyclosporine during ATN (n = 40). Allograft survival rates in these patients were also compared with those observed in cadaver kidney recipients with immediate graft function. The 1-year graft survival rate was significantly better in the ATN patients who received OKT3 prophylaxis (83%) than in those who were treated early with cyclosporine during the period of ATN (55%). The mean duration of OKT3 therapy was 11.1 +/- 2.5 days. There was no significant difference in 1-year graft survival rates between the ATN patients treated with OKT3 prophylaxis and patients who had immediate graft function (74%, 1985 through 1988 combined). Patient survival was unaffected by the occurrence of ATN or the postoperative immunosuppressive protocol. The duration of ATN was shortened (9.3 +/- 4.0 v 14.9 +/- 10.2 days), and the median time to first rejection was prolonged (23.5 v 11.0 days) by OKT3 prophylaxis compared with early cyclosporine.(ABSTRACT TRUNCATED AT 250 WORDS)