Renal transplantation has become the preferred means of treating end-stage renal disease. Episodes of allograft rejection have become the exception rather than the rule. The development of real-time ultrasound-guided allograft biopsy and adoption of the Banff criteria for histologic evaluation permit safe,accurate monitoring of graft histology. New immunosuppressive agents have drastically reduced the number of episodes of both primary and refractory rejection. Novel biologic agents in the form of monoclonal antibodies and soluble receptor hybrid molecules may serve to reduce the required doses of toxic chemical immunosuppressants and provide more specific immune suppression directed at those elements of the immune system involved in rejection of a given allograft. Development of assays to identify patients who demonstrate donor antigen-specific hyporeactivity is now feasible. Hopefully, these assays will serve as a guide for the reduction and possible removal of immunosuppressive agents from stable renal allograft recipients.