['Recipients of 0 HLA mismatch kidneys with prolonged cold ischemia times of longer than 36 hours do not have superior outcomes compared with recipients of kidneys with 1 or more mismatches.', 'Retrospective review.', 'Transplanation centers.', 'A total of 63,688 recipients who underwent transplantation between January 1, 1990, and July 31, 1998.', 'Delayed graft function, serum creatinine level, and patient and renal graft survival.', 'Recipients of 0 HLA mismatch kidneys with fewer than 36 hours of cold ischemia time had better 5-year graft survival (75%) when compared with recipients with 1 or more mismatches (67%) (P<.001). However, recipients of 0 HLA mismatch kidneys with longer than 36 hours of cold ischemia time did not have any graft survival advantage (71% in 0 HLA mismatch kidneys vs 72% in 1 or more mismatches, P =.24).'] Does prolonged cold ischemia time obviate the benefits of 0 HLA mismatches in renal transplantation?