During maintenance phase (5th-24th week after kidney transplantation) tacrolimus doses will be adjusted as in table 1. Tacrolimus blood level, BUN/Cr and urine 24 hour for Cr and protein will be perform on 5, 8, 12, 16, 20, 24 after transplantation. The physicians will modify the daily dose of tacrolimus according to their practice in order to achieve target range of trough concentration (3-5 ng/ml).