PHASE I: To demonstrate that the pharmacokinetics of Tacrolimus Hexal® assessed by the ratio of the AUC0-12h over a one month period post-transplantation is comparable to Prograf® in renal transplant patients. PHASE II (including the patients enrolled in Phase I, Phase II study will not be conducted): To demonstrate non-inferiority in renal function assessed by glomerular filtration rate (Nankivell formula) between both treatment arms at month 6 post-transplantation in renal transplant patients.