The primary objective of the present investigation is to compare the incidence or avoidance of corticosteroid use, as a measure of the decreased incidence of acute rejection episodes 6 and 12 months after primary renal transplantation in patients receiving three different immunosuppressive treatments. Current standard immunosuppression (group A: mycophenolate mofetil, tacrolimus and corticosteroids) will be compared to regimens with mycophenolate mofetil, daclizumab and a single week of corticosteroids as mainstay immunosuppression in combination with tacrolimus (group B) or (group C) where sirolimus, MMF and steroids will be continued.