This review covers the issue of kidney retransplantation. Patients waiting for a second transplant are increasing in number, and it is more and more difficult to find a suitable kidney. The main reasons are both clinical and immunological. Immunological problems are the most difficult to overcome. New techniques allow the identification of anti-HLA antibodies previously not easy to find. As a consequence, patients waiting for a new transplant are often hyperimmunized, and the cross-match is often positive. The authors discuss several immunosuppressive approaches for such patients and new allocation criteria to allow an easier retransplant. New allocation programs such as acceptable mismatch programs and paired kidney exchange programs are being implemented, and new drugs are now emerging allowing new desensitization criteria. Some of them are not yet on the market, but preliminary clinical studies show such drugs to be promising in a short time.