Induction immunosuppression with antilymphocyte antibodies has not been shown to improve cadaveric kidney allograft survival in randomized, controlled trials despite widespread use. This meta-analysis of randomized, controlled trials assessed the effectiveness of induction therapy in prolonging allograft survival. Studies of induction therapy were identified in Medline (1986 through 1996), using the terms "monoclonal antibodies" or "antilymphocyte serum," and "kidney transplantation," "human," and "clinical trial." Bibliographies, pharmaceutical manufacturers, the United Network for Organ Sharing, National Institutes of Health, and study authors were also consulted. Seven of 247 identified studies met the following inclusion criteria: (1) an adult study population; (2) assessment of antilymphocyte antibodies in the immediate posttransplant period; (3) a control arm of cyclosporine, azathioprine, and prednisone in the immediate posttransplant period; and (4) presentation of survival data. Two readers independently extracted protocol and survival data from each study. Summary odds ratios (fixed and random effects) and a rate ratio from proportional hazards regression at 2 yr were estimated to examine the effect of induction therapy on allograft survival. The summary odds ratios were both 0.66 (confidence interval [CI], 0.45 to 0.96; P = 0.03), and the rate ratio was 0.69 (CI, 0.49 to 0.97; P = 0.03), indicating a beneficial effect of induction therapy on allograft survival. Allograft survival was 85.6% (CI, 82.1 to 89.1%) in the induction therapy group and 79.6% (CI, 75.6 to 83.6%) in the conventional therapy group. These results were stable in a sensitivity analysis based on study quality. Allograft survival was prolonged with induction therapy compared with conventional immunosuppression. These data indicate a potential role for the routine use of induction therapy in renal transplantation to optimize the survival of cadaveric allografts.