Kidney transplantation is a life-saving treatment of choice for patients with end-stage renal disease (ESRD). There are several factors such as the degree of HLA compatibility between donor and the recipient, pretransplant blood transfusions, the recipient's state of immunoreactivity and sensitization, immunosuppressive therapy is given in post-operative period, etc. is determining together the success of transplant result. Donor selection is accepted as the most critical factor for the long-term success of the transplantation. Crossmatch between the serum of the recipient and lymphocytes of the donor is the most crucial step of donor selection for kidney transplantation.