Of 158 renal transplant recipients, 75 underwent excretory urography at some point during a six-year period, 24 hours to 7 years after transplantation. In 11 patients, renal papillary necrosis (RPN) was found. RPN was associated in 9 patients with one or more disease entities known to be the etiologic factor to RPN in nontransplanted kidneys. In 2 patients, previous rejection episodes were the probable case for RPN. Renal papillary necrosis, a rather late complication with renal allograft, was demonstrated in this population on an average of 28.1 months after transplantation.