In spite of improved one year renal allograft survival long-term results of renal transplantation did not change since several years. Progressive decline of graft function developing few years after renal transplantation remains a significant problem in renal replacement therapy. The clinical manifestation of progressive impairment of the kidney transplant is heterogeneous and the differential diagnosis of chronic graft rejection is difficult, even if histopathological examination is performed. Improvement of immunosuppressive therapy and avoidance of nonimmunologic factors which increase the risk of graft failure seem to influence markedly function of kidney grafts.