Suprarenal transplantation was performed in 15 dogs. In 14 the animal''s own gland was transplanted into another portion of the body, and in 1 a gland from another dog was transplanted. The sites used were the kidney, spleen, omentum and rectus muscle. The non-transplanted glands were removed 5-80 days after the 1st operation, whereupon death occurred in every case, with symptoms of suprarenal insufficiency. In 13 cases death resulted in less than 24 hrs. after operation (average 18 hrs.). The remaining 2 animals lived 94 and 95 hrs. respectively after the 2nd operation, succumbing with typical symptoms. In 1 animal a 2-stage double adrenal ablation with no transplantation was done, the dog dying 8 hrs. after removal of the 2nd gland. At autopsy no evidence of infection was seen. Early acquisition of blood supply by the transplant was microscopically demonstrated in all cases. Apparently living (cortical) cells were seen in some cases as late as 34 days after transplantation but none later. Apparently living medullary cells were seen in but 1 case, a graft 5 days old. In the kidney the graft apparently survived longest, while grafts in muscle were most rapidly destroyed and absorbed.