A technique is described for transplantation of the dog kidney from one animal to another without any interruption of the organ''s blood supply. An accessory circulation from the neck vessels of the donor animal is provided for the kidney during the time required to connect the renal vessels to the host''s vascular system. This procedure permits the study of the transplant rejection process without the ischemia which is a complicating factor in the technique usually employed. Transfer of the kidneys without ischemia does not markedly prolong the period of function, however the pathological changes which occur within the first few days following transplantation may be delayed.