Nineteen patients whose first renal homografts failed have undergone retransplantation; one patient has received a third homograft after the first two failed to function. As of July 1, 1966, eight of these patients are living, five with life-sustaining homografts that have been functioning for periods from 11 to 21 months. Three patients are being maintained with periodic hemodialyses. Second renal homografts functioned in six of seven patients who lost their first homografts because of technical problems and four of these patients are alive with functioning homografts. Second renal homografts were rejected by five of 10 patients who lost their first homografts because of rejection or thrombosis of the renal artery; only one of these patients is alive with a functioning homograft. We are reluctant to recommend retransplantation in patients who have rejected their first homograft, while we unhesitatingly recommend retransplantation in patients whose first homograft, though functioning, had to be removed because of technical problems.