There is little experience on the use of monoclonal antibodies that block the high-affinity interleukin-2 receptor (basiliximab and daclizumab) in sequential therapy in renal transplants with risk of delayed graft function. This study sougth to test the efficacy and safety of the substitution of anticalcineurins with two doses of basiliximab or daclizumab in the immediate posttransplant period for recipients at risk of delayed renal graft function. Immunosuppression consisted of steroids, mycophenolate mofetil, and two doses of basiliximab (20 mg/day) on days 0 and 4 posttransplant or daclizumab (1 mg/kg per day) on days 0 and 15 posttransplant. Anticalcineurins were not administered until the beginning of graft function. Among 49 recipients (mean age 63.5 +/- 10.5 years), 40 received a kidney from a donor over 60 years of age, three from a non-heart-beating donor, and six from donors with an acute elevation of serum creatinine to 2.4 +/- 0.86 (1.7-3.7). At a mean follow-up of 14.2 +/- 8.4 months, five patients experienced acute rejection episodes. Only 15 patients needed posttransplant dialysis (2.7 +/- 1.6). In 11 patients, cyclosporine (CsA) was introduced at 6 +/- 2.9 days posttransplant and in 37, tacrolimus on 8.6 +/- 3.6 days posttransplant. The incidence of kidney graft loss was 16.3%. Patient survival was 96%. Thirty-nine recipients are alive with functioning grafts, with mean serum creatinine of 1.4 mg/dL. In conclusion, substitution for anticalcineurins with interleukin-2-receptor blockade in the immediate posttransplant period for patients at risk of delayed graft function minimizes nephrotoxicity and reduces tubular necrosis, without increasing the risk of an acute rejection episode.