The use of animal organs could potentially alleviate the critical worldwide shortage of donor organs for clinical transplantation. Because of the strong immune response to xenografts, success will probably depend upon new strategies of immune suppression and induction of tolerance. Here we report our initial results using alpha-1,3-galactosyltransferase knockout (GalT-KO) donors and a tolerance induction approach. We have achieved life-supporting pig-to-baboon renal xenograft survivals of up to 83 d with normal creatinine levels.