Acute rejection still remains a major problem in organ transplantation and is a significant risk factor for chronic rejection, and chronic rejection is one of the most important causes of late graft loss. Current new immunosuppressive drugs such as tacrolimus, rapamycin and mycophenolate mofetil have been developed to reduce acute rejection and to improve renal allograft survival. More recently, antihuman antibodies, either monoclonal or polyclonal, have been developed to use for induction therapy at the time of transplantation or to treat rejection. Daclizumab, a new engineered human immunoglobulin monoclonal antibody to the interleukin-2 receptor a-subunit was approved to prevent acute rejection after solid organ transplantation. Data from clinical trials show daclizumab to be well tolerated in solid organ transplantation. It does not increase the incidence of infection, including cytomegalovirus infection.