Thirty of 377 patients gave evidence of peptic ulcer disease prior to renal transplantation. Prophylactic vagotomy with pyloroplasty or antrectomy was performed on 19 of these patients prior to transplantation, and 14 of 19 are well with transplants seven to 61 months later; only three of these patients have had posttransplant ulcer complications. No planned prophylactic operation was performed in 11 patients; nine of these patients bled in the pre- or post-transplant period. Only three of 347 patients without pretransplant evidence of ulcer bled in the posttransplant period. None of the patients with vagotomy-antrectomy showed evidence of recurrent bleeding, but patients with active ulcer disease pretransplant some-times had recurrences after vagotomy-pyloroplasty. One can conclude that pretransplant correction of the ulcerogenic tendency should be carried out and that antrectomy should be considered if active ulcers are present in the uremic transplant candidate.