One-hundred-and-twenty-six cadaveric renal transplantations were analyzed for the effect of post-transplant renal function on graft outcome. Thirty-one grafts functioned immediately after transplantation (Group 1), 54 grafts failed to function temporarily up to 8 posttransplant days as evidenced by urine output < 400 ml/day or hemodialysis support (Group 2), 33 grafts showed temporary nonfunction > 8 days (Group 3) and 8 grafts never functioned (group 4). Five-year graft failure rates were 6.5% (2/31), 13.0% (7/54), 42.4% (14/33) and 100% (8/8) for Groups 1, 2, 3 and 4, respectively. Actuarial 5-year graft survivals were 89.4%, 84.8%, 50% and 0% for Groups 1, 2, 3 and 4, respectively (p < 0.05). The most common cause of graft failure was the chronic rejection in 13, of which 9 were in Group 3. Acute rejection episodes during the first 3 months post-transplant in Group 3 (15 of 33, 45.5%) was slightly higher than that in Group 1 (10 of 30, 33.3%) or Group 2 (19 of 54, 35.2%) but the differences were not significant. Acute rejection episodes were associated with graft loss only 1 of 19 (5.3%) patients in Group 2 whereas 9 of 15 (47.4%) were seen in Group 3. The authors conclude that prolonged DGF is associated with a higher incidence of graft failure, particularly secondary to chronic rejection after 1 year posttransplant. Moreover, acute rejection based on prolonged DGF probably plays a major role in the development of chronic rejection.